Localization and band-gap pinning in semiconductor superlattices with layer-thickness fluctuations
Abstract
We consider (AlAs)_n/(GaAs)_n superlattices with random thickness fluctuations Delta-n around the nominal period n. Using three-dimensional pseudopotential plane-wave band theory, we show that (i) any amount Delta-n/n of thickness fluctuations leads to band-edge wavefunction localization, (ii) for small Delta-n/n the SL band gap is pinned at the gap level produced by a single layer with ``wrong'' thickness n + Delta-n, (iii) the bound states due to monolayer thickness fluctuations lead to significant band-gap reductions, (iv) <001> AlAs/GaAs SL's with monolayer thickness fluctuations have a direct band gap, while the ideal <001> SL's are indirect for n<4.
Keywords
Cite
@article{arxiv.mtrl-th/9507003,
title = {Localization and band-gap pinning in semiconductor superlattices with layer-thickness fluctuations},
author = {K. A. Mader and A. Zunger},
journal= {arXiv preprint arXiv:mtrl-th/9507003},
year = {2015}
}
Comments
10 pages, Revtex. 3 figures available at http://www.cecam.fr/~mader/elstruc.html . Published in Europhys. Lett. 31, 107 (95)