AMaSiS 2021 - Abstract
Schulz, Stefan
Tyndall National Institute, Ireland
Semiconductor nanostructures utilizing indium gallium nitride ((In,Ga)N) alloys have attracted considerable research interest due to their potential for optoelectronic device applications [1] but also recently as sources for non-classical light emission [2]. However, and in comparison to other III-V semiconductor heterostructures, (In,Ga)N-based systems exhibit very different fundamental properties. This starts with the underlying crystal structure (wurtzite vs. zincblende), ranges over to the presence of very strong electrostatic built-in fields and ultimately the observation of significant carrier localization effects in (In,Ga)N alloys [3]. In this talk, the impact of (random) alloy fluctuations on charge carrier transport, radiative and non-radiative recombination processes in (In,Ga)N-based heterostructures will be discussed.
Initially we will focus our attention on the temperature dependence of the radiative and non-radiative (Auger) recombination in (In,Ga)N quantum wells, using an atomistic tight-binding model [4]. Equipped with this knowledge, consequences for the thermal “droop” in (In,Ga)N-based light emitting diodes will be discussed [5]. In addition, we will present our approach to address the impact of random alloy fluctuations on the charge carrier transport in (In,Ga)N-based devices, employing a multi-scale simulation framework. As a test-bed, results for uni-polar (electron) transport in (In,Ga)N multi-quantum well systems will be presented [6].
In a second step, the electronic and optical properties of ultrathin, quasi-two dimensional (In,Ga)N layers embedded in GaN will be discussed [7]. These systems should emphideally circumvent the quantum confined Stark effect and thus the spatial separation of charge carriers, which limits the efficiency of the “conventional” (In,Ga)N quantum well systems mentioned above.
Finally, consequences of random alloy fluctuations for non-classical light emission, e.g. polarization entangled or twin photons, from (In,Ga)N quantum emphdots will be discussed [8]. Here, results from a fully atomistic many-body framework, combining tight-binding electronic structure theory and a configuration interaction scheme, will be presented.
Acknowledgments: This work was financially supported by Science Foundation Ireland (17/CDA/4789 and 12/RC/2276 P2). Furthermore, computing resources provided by Science Foundation Ireland (SFI) to the Tyndall National Institute and by the SFI and Higher Education Authority funded Irish Centre for High End Computing (ICHEC) are acknowledged.
References
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[4] J. M. McMahon emphet al., em Appl. Phys. Lett. bf 116 (2020), 181104.
[5] M. Meneghini emphet al., em J. Appl. Phys. bf 127 (2020), 211102.
[6] M. O'Donovan emphet al., em submitted (2021).
[7] D. S. P. Tanner emphet al., em Nanoscale bf 12 (2020), 20258.
[8] S. K. Patra emphet al., em Nano Lett. bf 20 (2020), 234.