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Important New Method for Studying Solar Materials

KioupakisSilicon.gif

Calculated (solid lines) and experimental (circles) absorption coefficient of silicon in the energy range between the indirect and direct gaps, for two temperatures.

The goal of research in this group in general has been to develop and use first-principles computational methods to understand, predict, and design novel electronic, optoelectronic, photovoltaic, and thermoelectric materials.

Using a NERSC NISE award, researchers were able to compute the phonon-assisted interband optical absorption spectrum of silicon entirely from first principles.

Nearly all commercially-available photovoltaic cells currently depend on this absorption process.

The new method is general enough to to study fundamental physics of other optoelectronic and photovoltaic materials and can address questions that are not accessible by experiment.

Used the BerkeleyGW software written by new NERSC USG consultant Jack Deslippe.

Work done by Jesse Noffsinger, Emmanouil Kioupakis, Chris G. Van de Walle, Steven G. Louie, and Marvin L. Cohen.

Publication: Jesse Noffsinger, Emmanouil Kioupakis, Chris G. Van de Walle, Steven G. Louie, and Marvin L. Cohen. Phonon-Assisted Optical Absorption in Silicon from First Principles. Phys. Rev. Lett. 108, 167402 (2012) 

For information on the BerkeleyGW code see BerkeleyGW: A massively parallel computer package for the calculation of the quasiparticle and optical properties of materials and nanostructures, Computer Physics Communications, Volume 183, Issue 6, June 2012, Pages 1269–1289