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Prize Talk: Rahman Prize for Computational Physics: First-principles studies of nonradiative recombination mechanisms

ORAL · Invited

Abstract

Carrier recombination plays a central role in optoelectronic devices. Radiative recombination enables the functionality of light-emitting diodes, lasers, phosphors, scintillators, and single-photon emitters for quantum information technologies; nonradiative recombination limits the efficiency of these devices, sometimes also triggering degradation. The ability to accurately calculate these processes is essential for analyzing experimental results and designing novel devices. Over the past 15 years, we have developed methodologies to quantitatively compute the relevant rates, and implemented them based on state-of-the art first-principles calculations.

I will focus on recombination at point defects and impurities. Multiphonon emission has typically been assumed to be the energy-dissipation mechanism [1,2], but fails to explain losses in materials with band gaps larger than about 2.5 eV. We have demonstrated the role of excited states [3] and of trap-assisted Auger-Meitner (AM) recombination [4]. Similar to band-to-band AM recombination [5], a trap-assisted AM process enables capture by exciting a carrier to a higher-energy state. For band gaps larger than 2.5 eV, the trap-assisted AM process results in recombination rates orders of magnitude larger than the rate governed by multiphonon emission alone.

I will illustrate these developments with examples for nitride-based light emitters as well as quantum defects. Our computational formalisms are general and can be applied to any defect or impurity in any semiconducting or insulating material.



I gratefully acknowledge collaborations with A. Alkauskas†, K. Bushick, K. Czelej, C. Dreyer, E. Kioupakis, G. Kresse, M. R. Lambert, W. Lee, J. L. Lyons, S. Mu, N. Pant, J. Shen, M. Turiansky, D. Wickramaratne, Q. Yan, X. Zhang, and F. Zhao.



[1] A. Alkauskas, Q. Yan, and C. G. Van de Walle, Phys. Rev. B 90, 075202 (2014).

[2] C. E. Dreyer, A. Alkauskas, J. L. Lyons, J. S. Speck, and C. G. Van de Walle, Appl. Phys. Lett. 108, 141101 (2016).

[3] A. Alkauskas, C. E. Dreyer, J. L. Lyons, and C. G. Van de Walle, Phys. Rev. B 93, 201304 (2016).

[4] F. Zhao, M. E. Turiansky, A. Alkauskas, and C. G. Van de Walle, Phys. Rev. Lett. 131, 056402 (2023).

[5] E. Kioupakis, D. Steiauf, P. Rinke, K. T. Delaney, and C. G. Van de Walle, Phys. Rev. B 92, 035207 (2015).

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Publication: [1] A. Alkauskas, Q. Yan, and C. G. Van de Walle, Phys. Rev. B 90, 075202 (2014).<br>[2] C. E. Dreyer, A. Alkauskas, J. L. Lyons, J. S. Speck, and C. G. Van de Walle, Appl. Phys. Lett. 108, 141101 (2016). <br>[3] A. Alkauskas, C. E. Dreyer, J. L. Lyons, and C. G. Van de Walle, Phys. Rev. B 93, 201304 (2016).<br>[4] F. Zhao, M. E. Turiansky, A. Alkauskas, and C. G. Van de Walle, Phys. Rev. Lett. 131, 056402 (2023).<br>[5] E. Kioupakis, D. Steiauf, P. Rinke, K. T. Delaney, and C. G. Van de Walle, Phys. Rev. B 92, 035207 (2015).

Presenters

  • Chris G Van de Walle

    University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, CA 93106-5050, U.S.A.

Authors

  • Chris G Van de Walle

    University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, CA 93106-5050, U.S.A.