Defect state investigation of amorphous silicon carbide using electron spin resonance and photothermal deflection spectroscopy

ORAL

Abstract

Amorphous silicon carbide alloys are being discussed as a possible top photovoltaic layer in photo electro-chemical cells used for water splitting. In order to be used as such, it is important that the effect of carbon concentration has on bonding, and thus the electronic and optical properties, is well understood. Electron spin resonance experiments, under varying experimental conditions, were performed to study the dangling bonds, which were found to be dominantly at the silicon atoms in these films. At room temperature, the spin count densities varied between 10$^{16}$ and 10$^{18}$ spins/cm$^{3}$. Photothermal deflection spectroscopy experiments were also performed in order to look at defects resulting in sub band-gap absorption where absorption is defined proportional to e$^{E/E'}$ with E' the inverse slope of the Urbach tail. We report slopes of between 70 meV to 83 meV. These increases in inverse slope correlate with increases in spin density.

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Authors

  • Brian J. Simonds

    Colorado School of Mines

  • J. Gallon

    Colorado School of Mines

  • Tining Su

    Colorado School of Mines, Colorado Schoo of Mines

  • Shufang Su

    Iowa State University, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, University of Arizona, Sandia National Laboratories, Physics Department, Texas Tech University, Lubbock, TX 79409-1051, Northwestern University, Texas Tech University, University of Utah Department of Physics, University of Toulouse-UPS, IRSAMC, Toulouse, France, University of Arizona, Department of Physics, National Institute of Advanced Industrial Science and Technology, Texas A\&M University, Midwest Proton Radiotherapy Institute, Birdville ISD, Universidad de Colima, Universidad de Buenos Aires, Brigham Young University, UT Atlington, MV Systems, Colorado State University, St. Petersburg Electrotechnical University, New Mexico State University, Texas State Univ., CAMD/LSU, Texas Christian University, Fort Worth, TX, North Side High School, Fort Worth, TX, Nitronex Corporation, Arizona State University, Angelo State University Department of Physics, Texas Tech University Deptarment of Electrical Engineering

  • P. Craig Taylor

    Colorado School of Mines