470975 First Principles Screening of Transparent Conducting Oxides Using Amobt

Tuesday, November 15, 2016: 5:00 PM
Yosemite A (Hilton San Francisco Union Square)
Alireza Faghaninia, Energy Environmental and Chemical Engineering, Washington University in Saint Louis, Saint Louis, MO and Cynthia S. Lo, Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO

Accurate ab initio electronic transport models, which bridge electronic and atomistic scales, can facilitate high throughput calculations and screening of semiconductor materials for energy applications. Previous attempts at screening new transparent conducting oxide (TCO) materials have focused on their average effective mass, due to the simplicity and speed of such calculations. This calculation is often simplified by being based solely on the shape of the band extrema. Although the approximate effective mass certainly gives a valuable prediction of material performance, it lacks sufficient complexity for accurate calculation of electronic properties, especially in degenerate semiconductors. In particular, electron-phonon interactions, which limit the mobility, particularly at room temperature, are ignored. Here we employ an ab initio transport Model in the Boltzmann Transport (aMoBT) framework, which accurately predicts the electrical mobility and conductivity of both n-type and p-type semiconductors. We calculate electronic structures within the Density Functional Theory framework, and then treat the non-equilibrium behavior of electrons and holes using the atomistic Boltzmann transport equation. We analyze more than 90 promising TCOs that were pre-screened using the average effective mass, and rank them based on their electron and/or hole conductivity, as limited by ionized impurity scattering and electron-phonon scattering mechanisms. We now report the most promising candidates from each of the n- and p-type semiconductors, and assert the utility of aMoBT, as incorporated into an automated atomistic calculation framework, in designing new materials for solar cell applications.

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