Xiaogan Liang
Staff Scientist, Nanofabrication Facilityxliang@lbl.gov
510.486.5337
Research Interests
- Advanced nanofabrication technologies, particular in nanoimprint lithography.
- Nanolithography in combination with bottom-up methods for assembling and tailoring nanomaterials into functional structures.
- Device applications in nanoelectronics, nanophotonics, photovoltaics, and nanofluidics.
Current Projects
- Single-Digit Nanofabrication Routes for Tailoring and Assembling Graphene into Functional Structures and Devices
The objective of this research is to develop new nanofabrication methods beyond the capabilities of current technologies for lithographically patterning graphene layers into single-digit nanometer scale. The produced graphene nanostructures will serve as reliable platforms for the investigation of new mesoscopic sciences, including transport properties of massless Dirac Fermions at the molecular scale, effects of edge morphology on graphene electronic structure, and ballistic behaviors of charged carriers. Such fundamental knowledge and technology will greatly expand the ability to control graphene properties and will be further developed to realize graphene-based energy-efficient devices in the future. Learn more
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Nanostructured Small-Molecular Weight Organic Compounds for Photovoltaic Applications
In order to fully harvest photo-generated excitons, densely-packed nanostructures with half-pitch smaller than exciton diffusion length (i.e., single-digit nanometer regime) are needed for nanoimprinting PV materials over large areas. Although nanoimprint with sub-10 nm pitch features has been widely demonstrated in polymeric materials, the direct imprinting of small-molecular weight organic compounds still suffers the problem related to the relatively poor stability of imprinted nanostructures. Such instability is attributed to the pronounced surface diffusion and self-faceting in such small-molecular compounds, especially at single-digit nanometer regime. In order to address this critical issue, I would like to systematically study the thermodynamic and kinetic behaviors of imprinted features in small-molecular organic compounds and hence identify the key processing parameters affecting the thermodynamically equilibrium profile of nanostructures. The experimental approaches and theoretical models developed in this work can serve as a useful guideline for producing stable nanostructures in various small-molecular compounds and improving the performance of PV cells. Second, novel nanofabrication routes based on self-assembly and nanoimprint will be applied to engineer the DA interface morphology and improve the key parameters as well as reliability of PV cells. In addition, a systematic model will be developed to guide the nanofabrication and help understand the device characterization. Learn more
Selected publications
- Xiaogan Liang, Yeon-Sik Jung, Ariel Ismach, Shiwu Wu, Deirdre L. Olynick, Stefano Cabrini, and Jeffery Bokor, “Formation of Bandgap and Subbands in Graphene Nanomeshes with Sub-10 nm Ribbon Width Fabricated via Nanoimprint Lithography,” Nano Lett. 10 (7), 2454–2460 (2010)
- Xiaogan Liang, Terasa Chen, Yeon-Sik Jung, Biwu Ma, Yoshikazu Miyamoto, Gan Han, Stefano Cabrini, and Deirdre L. Olynick, “Nanoimprint–Induced Molecular-Stacking and Pattern Stabilization in Substituted Phthalocyanine for Photovoltaic Applications,” ACS Nano 4 (5), 2627–2634 (2010).
- Xiaogan Liang, Valentina Giacometti, Ariel Ismach, Bruce D. Harteneck, Deirdre L. Olynick, and Stefano Cabrini, “Roller-Style Electrostatic Printing of Prepatterned Few-Layer-Graphenes,” Applied Physics Letters 96, 013109 (2010).
- X. Liang; A. Chang; Y. Zhang; B. Harteneck; H. Choo; D. Olynick; S. Cabrini, "Electrostatic Force – Assisted Exfoliation of Pre-Patterned Few-Layer-Graphenes into Device Sites" Nano Lett., Vol. 9, No. 1, (2009).
- Xiaogan Liang and Stephen Y. Chou, “A Nanogap Detector Inside Nanofluidic Channel for Fast Real-Time Label-Free DNA Analysis”, Nano Lett. 8 (5), 1472-1476 (2008).
Education
B.S. Physics, Peking University, Beijing, China
M.S. Condensed Matter Physics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
Ph.D. Electrical Engineering, Princeton University, Princeton, NJ
(Thesis: Advances in Nanoimprint Lithography and Applications in Nanofluidic Devices)
Princeton University, June 2008
Advisor: Professor Stephen Y. Chou
Past Professional Positions
Staff Scientist, The Molecular Foundry, Lawrence Berkeley National Laboratory, August 2010.
Material Science Postdoc Fellow, Nanofabrication Facility, The Molecular Foundry, Lawrence Berkeley National Laboratory, 2008-2010.
