Electronic and Optical Properties of Novel Phases of Silicon and Silicon-Based Derivatives

ORAL

Abstract

Recent discoveries of two novel phases of silicon, Si$_{\mathrm{20}}$ and Si$_{\mathrm{24}}$, lead to promises of quasi-direct band gap silicon crystals that are capable of complementing indirect-gap diamond cubic silicon for use in the solar cell industry. This work studies the quasiparticle excitations and optical spectra of these two structures, Si$_{\mathrm{20}}$ and Si$_{\mathrm{24}}$, assessing their suitability for use as photovoltaic materials. We carry out ab initio GW and GW-BSE calculations for the quasiparticle excitations and optical spectra, respectively, including self-energy and electron-hole interaction effects. This work was supported by NSF grant No. DMR10-1006184 and U.S. DOE under Contract No. DE-AC02-05CH11231. Computational resources have been provided by DOE at Lawrence Berkeley National Laboratory's NERSC facility.

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Authors

  • Chin Shen Ong

    Department of Physics, UC Berkeley and Lawrence Berkeley National Lab

  • Sangkook Choi

    Department of Physics, UC Berkeley and Lawrence Berkeley National Lab

  • Steven G. Louie

    University of California at Berkeley, Lawrence Berkeley National Lab, University of California - Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley; Materials Sciences Divisions, Lawrence Berkeley National Laboratory, Univ of California - Berkeley and Lawrence Berkeley National Lab, Department of Physics, UC Berkeley and Lawrence Berkeley National Lab, University of California, Berkeley and Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, UC Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley and Lawrence Berkeley National Lab, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA, UC Berkeley physics/ LBNL MSD