Nonradiative carrier capture rates at defects from first-principles calculations

ORAL

Abstract

We develop a computational methodology to determine nonradiative carrier capture rates at defects in wide-band-gap semiconductors. In our theoretical framework, we consider carrier capture via multiphonon emission as the dominant nonradiative mechanism for deep defects in wide-band-gap materials at low and moderate carrier densities. Our methodology is based on the static approximation for the electron-phonon coupling. We employ a state-of-the-art hybrid density functional approach to describe the electronic structure. For charged defect systems, the screening effect by excess carriers is taken into account. As test cases, we investigate deep centers including C$_{\rm N}$ and $V_{\rm Ga}$ in GaN and Li$_{\rm Zn}$ in ZnO. Calculated carrier capture rates are in good agreement with available experimental data. This work was supported by DOE, NSF, Swiss NSF, and by the UCSB SSLEC.

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Authors

  • Qimin Yan

    University of California at Santa Barbara, Materials Department, University of California, Santa Barbara, Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA, Materials Department, University of California at Santa Barbara

  • Audrius Alkauskas

    Materials Department, University of California, Santa Barbara, Materials Department, University of California at Santa Barbara

  • Chris Van de Walle

    University of California at Santa Barbara, Materials Department, University of California, Santa Barbara, Materials Department, University of California Santa Barbara, University of California, Santa Barbara, University of California, Santa Barbara Materials Department, University of California Santa Barbara, Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA, Materials Department, University of California at Santa Barbara