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Atomistic analysis of the electronic structure of m ‐plane InGaN/GaN quantum wells: Carrier localization effects in ground and excited states due to random alloy fluctuations
Author(s) -
Tanner Daniel P.,
Caro Miguel A.,
O'Reilly Eoin P.,
Schulz Stefan
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201552642
Subject(s) - condensed matter physics , quantum well , excited state , electronic structure , ground state , alloy , valence (chemistry) , materials science , physics , atomic physics , quantum mechanics , laser , composite material
We present a detailed atomistic analysis of the electronic properties of m ‐plane InGaN/GaN quantum wells. The tight‐binding model used treats realistically sized systems atomistically and accounts for compositional and structural inhomogeneities. Local variation in strain and built‐in potential arising from random alloy fluctuations are explicitly included in the model. Many energy states of the supercells considered are calculated in order to determine the impact of the alloy fluctuations on the electronic structure of the system under investigation. We find that while the electrons are relatively insensitive to the local indium environment, the hole states are highly sensitive to it and are subject to very strong localization effects. These effects persist several states into the valence band. This strong localization of the hole states leads to a very broad distribution of ground state energies in different random configurations. Furthermore, we see that the localization leads to poor overlap between different hole states resulting in a reduced probability of transfer of carriers between different states. This feature should play an important role for transport properties in m ‐plane InGaN/GaN QWs.