Molecular Foundry BLUR Opportunities

   

The Molecular Foundry is committed to supporting at least 8 summer undergraduate students from the College of Chemistry at UC Berkeley through the Berkeley Lab Undergraduate Research (BLUR) program.

The internship program period will span 10 weeks from early June through early August. Continuing research opportunities after this time period may be available.

Prospective undergraduate student researchers interested in this program are encouraged to review the project listings below prior to submitting their application (due in March). Projects of interest should be referenced in the application essay as described here.

Opportunities for Summer 2019

Intrabody-directed Quantum Dot Imaging

  • PI: Bruce Cohen (Bio, Group Website)
  • Short Description of Research Group's Focus: We invent novel optical probes–-luminescent nanocrystals and organic fluorophores-–as biosensors and single molecule probes, develop bioconjugation and targeting chemistries, and image live cells with these reagents. We engineer luminescent nanomaterials that are unusual and interesting, to address fundamental questions of cell function.
  • Project Description: Many nanocrystals exhibit brightness and stability far superior to conventional fluorophores, making them ideal as the bases for bioimaging reagents. We are developing bright, selective sensors for studying neuronal activity, including voltage sensors, sensors of neurotransmission in the brain, and ion sensors. A central challenge remains using these probes inside the cell, where they tend to be trapped in inappropriate cellular compartments. For this project, we have developed a means to introduce quantum dot nanocrystals into cells and want to target them to specific protein targets in live neurons. We are exploring using intrabodies, which are miniaturized antibodies designed to retain their conformation and function inside of the cell. These intrabodies target the intracellular domain of potassium channels that are critical for neuronal electrical activity but cannot be directly imaged in live neurons.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will synthesize quantum dot-intrabody conjugates for imaging live neurons
  • Intern's Role (types of tasks, techniques): Working with a Berkeley chemistry PhD student and neuroscience collaborators from UC Davis the intern will express and purify intrabodies, develop bioconjugation strategies for attachment to quantum dots, and assist in imaging these probes in neurons.
  • What can the intern expect to learn? Nanoparticle synthesis and bioconjugation, protein expression, some live cell imaging

Transport in Nanoscale Materials for Energy Applications.

  • PI: Jeff Urban (Bio, Group Website)
  • Short Description of Research Group's Focus: Our research group focuses on how transport of heat, charge, molecules is impacted by interfaces at the nanoscale. This is directly related to issues in water purification, CO2 sequestration, H2 fuel cells, catalysis, and thermoelectrics.
  • Project Description: We have three main related projects now, all of a similar flavor, involving materials synthesis/design, transport measurements, characterization, and (to the candidate's level of interest) some computational modeling. One area of ongoing research is in gas separations using hybrid polymer/porous crystal based membranes. Here we are seeking deeper insight into what interfacial bonding interactions are changing the behavior of the membranes enabling such high permeability and selectivity for gases of interest (e.g. CO2, CH4, etc.). We also have a project available in the design of related materials for selective ion recovery from water during purification. Here the concept is to design porous materials to selectively recover ions of interest (e.g. Li+ for batteries) from wastewater (where ions are abundant and must be removed). All of this will involve chemistry of these materials, incorporation into membranes, and basic transport characterization.
  • Main Project Goal or Research Question to be Addressed by the intern: Stated above, but essentially how do hard (molecular crystals) and soft (polymers) interact - and in particular, what interface interactions modulate the overall performance of the hybrid (hard/soft) bulk material that emerges?
  • Intern's Role (types of tasks, techniques): Listed above - synthesis, characterization.
  • What can the intern expect to learn? As above. Materials development, measurements of gas or ion permeability, basic structural characterization (XRD, ICP, etc)

Development of Chemical Etching Methods for Electron Beam Sources for Quantum Information Science Applications

  • PI(s): Andreas Schmid (Bio), Alexander Stibor
  • Short Description of Research Group's Focus: The recently funded QUINTESSENCE project at the Molecular Foundry aims to realize a combined quantum information science (QIS) electron microscope. An important part is the development of novel superconducting, entangled two-electron sources consisting of etched niobium or niobium nitrite nanotips. They are relevant for decoherence measurements and will be implemented as sources for the planned superconducting electron microscope in the 1K EM LDRD project and in the upcoming new quantum-SPLEEM (spin polarized low energy electron microscope).
  • Project Description: A key component in several new projects – QUINTESSENCE, 1K EM LDRD and quantum-SPLEEM – is the use of superconducting nanotip electron field emitters. This project aims to optimize nanotip etching methods for niobium (Nb) and niobium nitride (NbN). Those two materials are well suited due to their high transition temperature of 9.5 K and 16.5 K, respectively. It was demonstrated [1] that a superconducting niobium tip emits an electron beam with a ten times smaller energy width than conventional emitters (e.g. tungsten tips) and theory predicts a Nb tip to be a possible source of entangled free electrons with opposed spin and initial momentum through field emission of correlated Cooper pairs [2]. Such an entangled electron source would have a strong impact in QIS with several applications in decoherence measurements, electron microscopy and fundamental EPR-experiments.
    A method for etching Nb nanotips has been recently published in Ref. [3]. It turns out to be more elaborate and harder to control than standard tip fabrication techniques for tungsten. The project for the intern is to optimize and reproduce this chemical etching method to fabricate Nb tips with a radius below 10 nm. A polycrystalline Nb wire will be immersed into a KOH solution and etched in two steps, first by an alternating current and then by a periodic pulsed waveform. Finally, the tip will be annealed under ultrahigh vacuum (UHV) conditions. We also plan to cover these tips with a thin layer of gold to make them chemically inert (when thin enough, the gold layer will not decrease the superconducting emission properties). If rate of progress permits, the student may extend etch procedures to create NbN nanotips and characterize them in a scanning electron microscope.
    The field emission performance of tips produced by the student will be tested in an UHV setup with a cryostat where the electron beam characteristics can be measured with an energy analyzer and a multi-channel plate detector.

    [1] K. Nagaoka, T. Yamashita, S. Uchiyama, M. Yamada, H. Fujii, and C. Oshima, Monochromatic electron emission from the macroscopic quantum state of a superconductor, Nature 396, 557 (1998)
    [2] K. Yuasa, P. Facchi, R. Fazio, H. Nakazato, I. Ohba, S. Pascazio and S. Tasaki, Entanglement of electrons field-emitted from a superconductor, Phys. Rev. B 79, 180503R (2009)
    [3] J.-L. Hou, W.-T. Chang, C.-C. Shih, Y.-F. Yu, T.-Y. Fu and I.-S. Hwang, A nanoemitter based on a superconducting material, Appl. Phys. Lett. 108, 263107 (2016)
  • Main Project Goal or Research Question to be Addressed by the intern: The goal is to explore and optimize Nb and NbN nanotip etching protocols, building on approaches known from literature and from our preliminary work. Performance measure will be field emission testing, goals include beam stability, intensity, and coherence. Ultimate goal is the generation of electron beams that can be analyzed for two-electron correlated and entangled emission with low energy spread.
  • Intern's Role (types of tasks, techniques): The intern will set up a tip etching station for controlled and reproducible Nb and NbN nanotip fabrication procedures. He or she will optimize existing etching techniques and characterize the tip shape and size in a scanning electron microscope. He or she will use electrochemical methods to coat tips with a gold layer and implement tips into a vacuum setup for surface annealing and electron field emission characterization.
  • What can the intern expect to learn? The intern will learn nanotip fabrication methods by chemical etching. He or she will be trained on a scanning electron microscope and how to work with an UHV setup. The student will also gain some experience in electron optics and cryo-techniques and get insight in the fundamental role of coherent electrons in QIS.

Design and Synthesis of Sequence-defined Peptoids that Fold and Self-assemble into Defined Structures.

  • PI: Ron Zuckermann (Bio, Group Website)
  • Short Description of Research Group's Focus: We have developed a new class of bio-inspired polymers, called peptoids, that can mimic many properties of peptides and proteins, yet they are more stable, and are easier and cheaper to make. We make peptoids using automated robotic synthesizers, and are able to look at their self-assembly behavior by optical microscopy, electron microscopy and a variety of spectroscopic methods. Come join us to help discover new biomimetic structures made from these non-natural polymers! More info at www.ronznet.com
  • Project Description: Nature builds precisely structured materials on the nanometer scale all the time. Proteins and nucleic acids, for example, are linear polymer chains that can fold up into amazingly intricate and defined 3D structures that perform all kinds of sophisticated functions. Can we learn how to apply these architectural principles to non-natural polymers? If so, we could make catalytic and molecular recognition materials that would be much tougher and longer lasting than enzymes, receptors or antibodies. This project will explore ways to design and synthesis synthetic peptoid polymers that can fold into protein-like structures to create artificial proteins.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will study the impact of monomer sequence on the self-assembly properties of a series of peptoid polymers. We have already discovered simple peptoid sequences that form well-defined nanosheets, nanotubes and helices. Now we seek to engineer these structures to introduce protein-like functions into them by tuning their structures.
  • Intern's Role (types of tasks, techniques): The intern will lead their own project to design their own molecules to synthesize and then study their assembly and functional properties.
  • What can the intern expect to learn? The intern will learn about the solid-phase synthesis of sequence-defined polymers, computational modeling of their 3D structures, biopolymer analysis and purification using HPLC and mass spectrometry, and characterization by confocal fluorescence microscopy, AFM and SEM.

Designed Synthesis of Robust sp2 Carbon-conjugated Covalent Organic Frameworks: Towards Advanced Applications

  • PI: Yi Liu (Bio, Group Website)
  • Short Description of Research Group's Focus: 1) organic-inorganic hetero-material frameworks as next generation optoelectronic materials, 2) self-assembly of porous 2D and 3D framework materials with controlled structure and engineered function, and 3) design and synthesis of new organic semiconductors for organic electronics, and fundamental understanding of the associated electronic processes.
  • Project Description: Covalent organic frameworks (COFs) that exploit conjugated bonding based on sp 2 -hybridized carbons could impart materials with exceptional stability, electronic, magnetic and optical properties. However, the synthesis of sp 2 carbon-conjugated COFs remains challenging and only a very limited number of such COFs have been constructed since its first report in 2016. With these in mind, we propose to design and synthesize novel 2D and 3D sp 2 carbon-conjugated COFs, which allow tuning of the optical and electrical behavior and can be applied in wide applications such as energy storage, sensing and catalysis, which has not yet been explored due to the synthetic difficulties mentioned above.
  • Main Project Goal or Research Question to be Addressed by the intern: Tackle the synthetic difficulties of novel sp 2 carbon-conjugated COFs and explore new electrical and optical applications associated with COFs.
  • Intern's Role (types of tasks, techniques): The intern will perform the synthesis of COFs linkers and screen synthetic conditions for COF growth, perform basic characterizations including PXRD, N 2 sorption analysis, FTIR, UV-Vis, SEM and etc.
  • What can the intern expect to learn? The intern will learn the basic organic synthesis of small molecules, principles of design and synthesis of covalent organic frameworks. Moreover, the intern will learn how to operate and analyze characterizations of porous materials such as PXRD, N 2 sorption analysis, FTIR, UV- Vis, SEM and etc.

para-Azaquinodimethanes (p-AQMs): A Stable Quinoidal Motif with High Mobilities for Novel Electrochemical Transistor Geometries

  • PI: Yi Liu (Bio, Group Website)
  • Short Description of Research Group's Focus: The Liu group is focused on pushing the boundaries of organic electronics from 1 st generation organic devices (OPVs, OFETs, etc.) into 2 nd generation devices such as organic electrochemical transistors (OECTs) through the generation of novel conjugated organic motifs. We are currently exploring the effects of quinoidal character on electronics in both small molecule and conjugated polymeric systems.
  • Project Description: A family of p-AQM-containing conjugated polymers functionalized with oligoethylene glycol solubilizing chains have been predicted to be high performing OECT active materials. These polymers are closely related to ones previously synthesized by the Liu group, but their synthesis is not expected to be trivial. Upon the successful generation of these polymers, their chemical and thin-film properties will be characterized and OECTs will be engineered in collaboration with the Rivnay group at Northwestern University.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will set out to synthesize a family of p-AQM-containing conjugated polymers for use in OECTs that are predicted to be high-performing.
  • Intern's Role (types of tasks, techniques): The intern will work towards the synthesis and characterization of a specific p-AQM-containing polymer, whereupon the intern’s goals will shift to the synthesis of related polymers in an attempt to optimize the performance of these polymers in OECTs.
  • What can the intern expect to learn? The intern will gain an in-depth understanding of synthetic organic chemistry as well as the characterization techniques used therein. Similarly, the intern will come to learn the synthetic and characterization techniques employed in polymer chemistry. Finally, the intern will learn the basics of device engineering and the theory underpinning the characterization thereof.

New Spintronics: An ab initio Investigation of Potential Half-metallic Ferromagnetism in BaMn2X2 (X = Sb, P) Compounds.

  • PI: Sinead Griffin (Bio)
  • Short Description of Research Group's Focus: We are a multidisciplinary theory and computation group that solves materials challenges ranging from next-generation technologies to high-energy physics. We do this by combining theoretical models, atomistic simulations, and high- throughput database searches, to understand how atoms in crystals combine to give functional properties.
  • Project Description: The next-generation of microelectronics will rely on harnessing novel phenomena and materials to surpass ‘Moore’s Law’. A promising route is ‘spintronics’; these aim to augment standard charge-based capacitors with a spin degree of freedom. Half-metallic ferromagnetism is a rare -- yet technologically valuable -- phenomenon in spintronic materials, making novel half metals much sought-after. We previously predicted a new class of half metals based on BaMn2As2 using first-principles calculations, which were subsequently verified in experiments. The key functional driver in these materials, and the cause of half-metallicity, is the length of Mn-As bond in the crystal structure. This project aims to further understand the role of the Mn-X (X=Sb, P) bonds in potential half-metallicity in the BaMn2Sb2 and BaMn2P2 systems, which have recently been synthesized, and to determine whether these classes of compounds are new half-metals.
  • Main Project Goal or Research Question to be Addressed by the intern: Using first-principles calculations based on Density Functional Theory (DFT), the project will address whether BaMn2Sb2 and BaMn2P2 compounds become half- metallic with alloying and pressure, and their proximity to half-metallicity throughout the phase diagram. If half-metallicity is not present, the project will contrast these two classes of compounds with the known half-metallic BaMn2As2 systems to determine the key features for half-metallicity.
  • Intern's Role (types of tasks, techniques): The intern will perform the primary first-principles calculations for the duration of the project. They will build up the structure and input files to carry out the calculations, and manage and maintain calculations on supercomputing clusters. They will be responsible for gathering the data they have generated, visualizing their results into meaningful graphs, and presenting their results in written, poster and oral forms. The intern will also perform literature searches on the direct research problem and on related topics.
  • What can the intern expect to learn?
    • Proficiency in performing state-of-the-art first-principles calculations based on Density Functional Theory, which is the working-horse for materials simulation across physics, chemistry and materials science
    • A practical, hands-on knowledge of Linux, command-based computing, supercomputing, and several aspects of modern materials simulations tools
    • How to interpret data, develop hypotheses, and explain results in terms of existing knowledge in the field
    • Best practices in analyzing and presenting scientific results visually and through both written and oral presentations
    • How to develop knowledge of a new topic: the intern is not expected to have previous knowledge of the field (spintronics), but will learn the key problems and materials issues in the field during the project, and how to gather and analyze information

Improving Enzyme Cascade Efficiency Through Controlled Assembly at the S-layer Surface

  • PI: Paul Ashby (Bio)
  • Short Description of Research Group's Focus: The Ashby group aims to design materials whose nanoscale structure improves their functional properties. We use imaging techniques to spatially resolve physical and chemical properties and rely heavily on Atomic Force Microscopy (AFM) because it nondestructively probes the surface of materials in-situ.
  • Project Description: We aim to create highly efficient enzyme cascades by colocalizing enzymes through their attachment to S-layer protein assembled at a surface. Enzyme cascades in nature are often associated with membranes or surfaces to colocalize enzymes and improve reactant/product transport. S-layers are proteins that form an exquisitely crystalline coat on archaea and some bacteria. We will use the ability of S-layers to form large 2D crystals along with their ready functionalization to covalently attach and organize enzymes at the surface to improve yield.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will focus on creating supported S-layer surfaces with large crystalline domains and increasing the density of catalysts covalently attached to the S-layer.
  • Intern's Role (types of tasks, techniques): The intern’s role will be to prepare S-layers with catalysts under various conditions and characterize their them using Atomic Force Microscopy and Scanning Electron Microscopy.
  • What can the intern expect to learn? The intern is expected to learn one step chemical reactions to prepare functionalized S-layers and their assembly techniques followed by high resolution in-situ imaging using Atomic Force Microscopy.

Jamming and Relaxation Dynamics of Structured Liquids

  • PI: Paul Ashby (Bio)
  • Short Description of Research Group's Focus: The Ashby group aims to design materials whose nanoscale structure improves their functional properties. We use imaging techniques to spatially resolve physical and chemical properties and rely heavily on Atomic Force Microscopy (AFM) because it nondestructively probes the surface of materials in-situ.
  • Project Description: Structured liquids are liquid in liquid systems that persist in shape due to a solid like film of nanoparticles jammed at the interface. They can be used for reconfigurable reaction vessels and 3D printing of fluidic channels. Specific physical properties of the jammed nanoparticle film are essential for effectively structuring the liquids. We will investigate the structure of the interfacial films using in-situ Atomic Force Microscopy and probe their rheological properties to determine how the structure of these jammed films influences their functional properties.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will seek to determine the structure of interfacial nanoparticle films as they transition to the jammed sate.
  • Intern's Role (types of tasks, techniques): The intern’s role will be to prepare interfaces of liquids with various concentrations of nanoparticles and surfactant and to measure the interfacial surface tension and nanostructure with the Atomic Force Microscope.
  • What can the intern expect to learn? The intern can expect to learn in-situ Atomic Force Microscopy and pendant drop tensiometry along with an introduction to the rheology of complex fluids.

Designing Organic Frameworks for Laser Refrigeration

  • PI: Liang Tan (Bio)
  • Short Description of Research Group's Focus: We use first-principles calculations and theory to understand light-matter interactions at the nanoscale. We are interested in the discovery new photophysical phenomena, their realization in nanomaterials, and their applications in optoelectronics, light harvesting, and quantum information science.
  • Project Description: Most materials heat up when placed under a light source. In contrast, laser refrigeration is the cooling of a material under laser illumination. This phenomenon has been observed in cold atomic gases, but examples of solid state laser cooling has been restricted a few rare-earth doped glasses. The development of solid state laser cooling will enable new refrigeration applications, such as spot-cooling of micro- and nanoscale objects, for which the vibration and size limitations of conventional mechanical refrigeration methods are unsuitable. In this project, we will design metal organic frameworks (MOFs) and covalent organic frameworks (COFs) for laser refrigeration applications. We will search the diverse chemical structures of MOFs and COFs for structural motifs conducive to laser refrigeration. The main mechanism for laser refrigeration is the removal of heat by fluorescence at light frequencies higher than the incident laser frequency. We expect that these candidate MOFs and COFs will have fluorescence rates much faster than competing energy loss mechanisms, resulting in high cooling efficiencies.
  • Main Project Goal or Research Question to be Addressed by the intern: Identifying MOFs and COFs likely to exhibit high laser cooling efficiencies. Is it possible for organic frameworks to be better laser refrigerators than the current benchmark materials?
  • Intern's Role (types of tasks, techniques): The intern will carry out calculations to estimate the laser cooling efficiencies of MOFs and COFs. This will involve high-throughput screening of materials databases, together with the development of tools to identify and generate chemical motifs leading to high laser cooling efficiencies.
  • What can the intern expect to learn? Over the course of this project, the intern will learn about fluorescence processes in materials, and the microscopic theory behind them. The quantum mechanics that underlies these processes is transferrable to many other photochemical and photophysical phenomena. Besides this scientific knowledge, the intern will learn technical skills such as how to access materials databases by writing their own custom scripts to pull and analyze data.

Ultrathin Hexagonal Boron Nitride films as Ideal Substrates for Optoelectronic Materials

  • PI: Shaul Aloni (Bio) Collaborators: Tevye Kuykendall, Adam Schwartzberg
  • Short Description of Research Group's Focus: Our group is working on study of low dimensional inorganic semiconductors. The work spans synthetic efforts, development of novel characterization techniques and device fabrication to control charge distribution and flow for light emitting and energy harvesting as well as other optoelectronic application like quantum computing and sensing.
  • Project Description: Quantum materials have fascinating properties due to collective coupling of electrons, phonons and photons leading to new quasiparticle states. Our ability to study these materials depends in our capability to synthesize these materials with high specificity and control of their composition and structure. Their properties are often defined more by the support on which they are grown then their intrinsic properties. Over the last few years h-BN emerged as the ideal support for their synthesis, characterization and implementation. Synthesis of h-BN is challenging by itself and achieving single atomic layer control is still to be achieved. In this project we are developing growth of h-BN via metalorganic chemical vapor deposition (MOCVD) on metallic (Au, Cu and graphene) as well as semicpnducting (GaN and SiC) substartes.
  • Main Project Goal or Research Question to be Addressed by the intern: The goal of this project is to grow ultra-thin h-BN films via Molecular beam epitaxy with single atomic layer precision. The intern will join the team in effort to optimize the growth parameters of ultra-thin h-BN films on variety of substrates.
  • Intern's Role (types of tasks, techniques): The intern’s main responsibility will be to characterize the as grown films via optical, scanning electron microscopy (SEM) and Raman and FTIR spectroscopies, as well as to participate in synthetic experiments and x-ray photoelectron spectroscopy to flash the relation between synthetic parameters and material properties.
  • What can the intern expect to learn? Intern will learn to operate SEM and Raman and FTIR spectrometers and basic data analysis techniques (Image and spectrum data processing). Moreover, the intern should expect participate in, and provide input for the MOCVD growth experiments.

When Rare Events Become Typical: Life at the Extremes of the Probability Distribution

  • PI: Stephen Whitelam (Bio, Group Website)
  • Short Description of Research Group's Focus: An outstanding problem of materials science is to develop predictive, microscopic rules for self-assembly: given a collection of nanoscale building blocks, such as small molecules, nanoparticles, or proteins, how will they self-assemble? As time evolves, what phases and structures will they form, and what will be the yield of the target structure when – if – it assembles? Basic understanding of this nature is required to achieve the mission of the Molecular Foundry, the atomic-level design, creation and control of energy-relevant materials. My group uses the tools and techniques of statistical mechanics to address these questions. http://nanotheory.lbl.gov/people/SteveWhitelam.html
  • Project Description: Dynamical systems display typical behavior, but also fluctuations about this behavior. For instance, a biological motor powered by ATP may run forward on average, but will occasionally stall or move back a step. Furthermore, extremely rare fluctuations are also possible: for instance, the motor could run in reverse for many steps. Quantifying very rare behavior is important for the simple reason that it can have dramatic consequences: e.g. a backwards-moving motor could become jammed or detached. In this project we will study the rare dynamics of nanomachines using computer simulations.
  • Main Project Goal or Research Question to be Addressed by the intern: Understand how to quantify very rare behavior using simple computational tricks that introduce a modified reference frame in which rare events become typical. This area of research is an active one in nonequilibrium statistical mechanics. The tools and ideas underpinning this work are relevant to rare events in nanosystems, but also to the modeling of other complex phenomena such as earthquakes and financial markets.
  • Intern's Role (types of tasks, techniques): Work with Whitelam and Foundry User Daniel Jacobson (Caltech) to make computer models of nanomachines. Work out how to calculate rare events and free-energy differences for these systems using established theories (e.g. the Jarzynski identity) and our own simulation methods.
  • What can the intern expect to learn? The basic ideas and simulation techniques required to quantify probability distributions for complex systems. A basic introduction to the mathematical field of “large deviations”, which provides a framework for studying rare events in many different physical systems.

The Effect of Atomic Layer Deposited Thin Films on Superconducting Qubit Decoherence Times

  • PI: Adam Schwartzberg (Bio) Collaborators: Shaul Aloni, Stefano Cabrini
  • Short Description of Research Group's Focus: Our team focuses on thin film growth and nano-fabrication of new optoelectronic materials for quantum information, energy harvesting, and next generation computing using atomic layer deposition, metal organic chemical vapor deposition, and the Foundry's nanofabrication toolset. We assemble and structure these materials to create new, complex systems which we study using optical (time resolved and static), physical (scanning probe) and electron techniques (e.g. scanning and transmission), and combinations thereof.
  • Project Description: Qubits, the basic unit of quantum information, have been successfully created as superconducting Josephson-Junction devices. One of the main limitations of these devices is their sensitivity to surrounding material, greatly limiting how they may be fabricated, and the density at which they can be packed on a chip. Atomic layer deposited thin films as a membrane support is one path to solving both of these problems. Ultra-thin substrates will allow for greater packing density in 3-dimensions, while minimizing the volume of material that the qubit resonator interacts with. However, there have been limited studies to understand how atomic layer deposition (ALD) grown materials interact with qubit resonators, and how the growth process can be manipulated to create high performance qubit devices. In this project we will be taking functional superconducting resonator devices and growing a variety of materials over them to study the affect these films have on the devices. This information will then be used to advance the development of next generation Josephson-Junction qubit device fabrication.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will be studying how ALD grown films affect qubit resonator coherence time in collaboration with the Siddiqi group at UCB.
  • Intern's Role (types of tasks, techniques): The intern will be growing a variety of ALD films on pre-fabricated devices and working with the Siddiqi group to determine the effect of these films on the qubit resonators.
  • What can the intern expect to learn? The intern will learn how to perform ALD, as well as in-situ spectroscopic ellipsometry for characterizing film quality. The intern will also work with a staff member to characterize the composition of the ALD films using x-ray photoelectron spectroscopy.

Fabrication of Sub-5 nm Free-standing Dielectric Membranes for Spectroscopy and Electron Microscopy

  • PI: Adam Schwartzberg (Bio) Collaborators: Shadul Aloni, Stefano Cabrini, Michael Elowson
  • Short Description of Research Group's Focus: Our team focuses on thin film growth and nano-fabrication of new optoelectronic materials for quantum information, energy harvesting, and next generation computing using atomic layer deposition and metal organic chemical vapor deposition. We assemble and structure these materials to create new, complex systems which we study using optical (time resolved and static), physical (scanning probe), electron (e.g. scanning and transmission), and combinations thereof.
  • Project Description: In high energy spectroscopy (e.g. x-ray photoelectron spectroscopy) and electron microscopy there is a signifiant need for supporting samples on interest on robust ultra-thin transparent substrates. Graphene has been used to great effect for these types of experiments. However, handling graphene and creating reproducible, high quality substrates in this way is extremely difficult. We have been exploring the use of atomic layer deposition (ALD) as a method for creating these membrane supports without much greater stability and reproducibility. ALD is a technique that allows for the creation of a wide range of materials as conformal thin films with control over thickness at the sub-angstrom level. In this project we will explore a variety of ALD materials and processes for creating membranes, as well as some new fabrication processes to improve membrane quality.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will be studying both the membrane fabrication process and ALD growth of interesting membrane materials.
  • Intern's Role (types of tasks, techniques): The intern will be performing ALD growth and fabricating the membrane support chips
  • What can the intern expect to learn? The intern will learn how to perform ALD processes under a variety of conditions and for several materials. To characterize these films the intern will learn how to use spectroscopic ellipsometry and scanning electron microscopy. The intern will also learn several fabrication techniques including wet and dry etching, and photolithography.

Design and Fabrication of a Rotational MEMS Device for Rapid Electron Tomography

  • PI: Stefano Cabrini (Bio) Collaborators: Mary Scott, Michael Elowson
  • Short Description of Research Group's Focus: Our team combines the expertise of nanofabrication and electron beam microscopy. The main goal is to produce a MEMS-based rotational stage that can be used in the TEM chamber and work in the presence of a highly energetic electron beam. This fast and precise stage will allow for quick tomography of nanoparticles for high throughput analysis.
  • Project Description: Microelectromechanical Systems (MEMS) encompasses the study and technological development of mechanical and electro-mechanical structures made using micro- and nanofabrication techniques. This project will develop a MEMS device that rapidly rotates an object for electron tomography experiments. 3D tomographic imaging (retrieving 3D structure from a set of 2D projections) is widely used by electron microscopy to measure structure/property relationships. The Molecular Foundry has established itself as a world leader in tomography, however tomography requires extensive acquisition time and electron dose due to the inaccurate rotation mechanism during acquisition and intensive post-processing required. Miniaturization of the components will solve multiple key issues including rotation speed, positioning accuracy, and sample drift. Successful fabrication of the device would enable high throughput, low-dose and in situ TEM experiments not possible anywhere else in the world. MEMS devices for rotation around a center axis have previously been developed using electrostatic [1,2] mechanisms for actuation. Flexure beams arranged monolithically in series around a center point allow for potentially large rotational displacements with minimal shift of the center axis, all while avoiding friction and wear [1,2]. During this six-month internship, the student will contribute to the design and fabrication of the MEMS rotational device for electron tomography. Simulation of the deflection and stress/strain of the mechanical structures using finite element analysis are another potential focus of the project.

    [1] Marc Stranczl et al., Journal Of Microelectromechanical Systems, 21, 3,. 605-620, 2012.
    [2] S. M. Barnes et al., “Torsional Ratcheting Actuating System,” Sandia National Laboratories.
  • Main Project Goal or Research Question to be Addressed by the intern: The intern will be work on the MEMS design and fabrication. Few architectures are able to obtain the desired rotational range, and the most efficient and practical design must be found and characterized.
  • Intern's Role (types of tasks, techniques): The intern will apply the fabrication techniques available at the Molecular Foundry and potentially run MEMS simulation software.
  • What can the intern expect to learn? The intern will learn how to perform optical lithography, plasma and wet etching, scanning electron microscopy, and other cleanroom techniques.

Sustainable Plastics with Infinite Recyclability

  • PI: Brett Helms (Bio, Group Website)
  • Short Description of Research Group's Focus: Research in the Helms Group is devoted to understanding and controlling the dynamic behavior of materials systems typically composed of organics, polymers, or nanocrystals. We harness this knowledge to advance technologies related to energy, sustainability, water, and food quality, where our unique approaches break new ground. We thrive as a team, empowered by the diversity of perspectives we bring to the problem at hand.
  • Project Description: Our group has recently discovered a new class of infinitely recyclable plastics based on polymers that feature dynamic covalent bonds. Building on this proof-of-concept work, this project aims to elucidate the design rules governing recyclability at the molecular level. The intern will introduce to our vitrimers linear polyether segments that vary in conformational degrees of freedom (i.e., polyoxirane, polyoxetane, polyoxolane, etc.) and overall loading in the network. This library allows the first systematic study of vitrimer structure–property–recyclability space for plastics covering the complete spectrum of polymer properties, from glasses to elastomers. Such plastics, particularly the latter, are highly attractive for 3-D printing, recyclable textiles, packaging for food and beverage, and other consumer goods that would otherwise be landfilled.
  • Main Project Goal or Research Question to be Addressed by the intern: What is the molecular basis for the infinite recyclability of vitrimers? The goal of this research is to develop the materials chemistry of infinitely recyclable plastics with tunable mechanical properties, spanning polymer glasses to elastomers.
  • Intern's Role (types of tasks, techniques): The intern will synthesize polyoxiranes, polyoxetanes, polyoxolanes using living cationic polymerization methods and carry out chain-end modifications allowing them to be incorporated into a dynamic covalent polymer network. The intern will vary the loading of these linear polymers in the overall vitrimer network using a new class of green and “clickable” polycondensation reactions, where water is the only byproduct. With these materials in hand, the intern will evaluate their performance as plastics with differentiated characteristics as well as their recyclability, after having been compounded with dyes, plasticizers, flame retardants, and other additives that are commonly used in plastics today, but for which no scalable upcycling solution has been found for when they are encountered in a waste steam.
  • What can the intern expect to learn? The intern will learn principles of polymer synthesis, processing, compounding, reconfigurability, and recycling. The intern will acquire technical skills in Schlenk line use for air free synthesis as well as in soft matter materials characterization using NMR, DSC, and TGA techniques. The intern will also learn how to process and mold polymers into standard formats for recycling and for mechanical testing by DMA and tensiometry. Some formulations may also be amenable to 3-D printing, which will be a target focus for the polymer design space. The intern will also enrich their understanding of modern laboratory practices, from experimental design to productively using digital resources for technical communication and workflow planning (OneNote, Slack, etc.) with the team in a highly supportive and dynamic environment.

Creating Well-defined Defect Sites in Metal-Organic Frameworks

  • PI: Jian Zhang (Bio)
  • Short Description of Research Group's Focus: The Zhang group is focusing on the design and synthesis novel nanoporous organic-inorganic hybrid materials for catalytic and photocatalytic applications. In particular, building a well- defined catalytic center within porous materials is one of the synthetic goals. Such centers are expected to serve as the model catalysts for solar fuel generation and industrially important chemical reactions to provide a fundamental understanding of the structure-activity relationships and reaction mechanisms.
  • Project Description: Metal-organic frameworks (MOFs) are a class of crystalline porous solids that are constructed via the self-assembly of organic linkers with inorganic metal ions or clusters. The large surface area, pore volume, and unlimited combination of both organic and inorganic component makes MOFs a new generation of porous materials that could be potentially used in various fields including gas storage and separation, sensing, imaging, energy storage, drug delivery, and catalysis. In particular, MOFs offer an ideal platform for building catalyst models that are based on inorganic metal-oxo clusters with atomistic precision. This project aims to create defects sites within the clusters using controlled synthesis. Combined with X-ray analysis and theoretical calculation, it is expected to build a structure-activity relationships and better understanding of reaction mechanisms.
  • Main Project Goal or Research Question to be Addressed by the intern: The goal of the project is to use the doping strategy to incorporate structurally distinct linkers to create well-defined inorganic nodes that incorporated defect sites at the metal-oxo clusters. The potential phase separation is the challenge that needs to be synthetically addressed.
  • Intern's Role (types of tasks, techniques): The intern will be working on the synthesis of custom-designed organic ligands and their corresponding zirconium- and aluminum-based MOFs via solvothermal synthesis. After doping with transition metals within the obtained MOFs, the structure models will be constructed via X-ray techniques. These models will be used further to correlated with their catalytic performance.
  • What can the intern expect to learn? The student can expect to learn basic molecular materials synthesis and characterization skills, such as Schlenk techniques, NMR, mass spec, IR/Raman, X-ray crystallography (single-crystal and powder diffraction), gas adsorption, electrochemistry etc. Students will learn to take multiple approaches to ask and answer scientific questions and prepare scientific presentations.

 

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