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Theory of electron confinement and electron effective mass in dilute nitride alloys and heterostructures
Author(s) -
O'Reilly E. P.,
Lindsay A.,
Tomić S.,
Klar P. J.
Publication year - 2004
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.200405249
Subject(s) - bowing , effective mass (spring–mass system) , hydrostatic pressure , electron , condensed matter physics , heterojunction , electronic band structure , band gap , conduction band , quantum well , excited state , nitride , chemistry , materials science , atomic physics , physics , nanotechnology , optics , thermodynamics , laser , philosophy , theology , quantum mechanics , layer (electronics)
The band‐anti‐crossing (BAC) model describes the strong band‐gap bowing at low N composition x in Ga(In)N x As 1– x in terms of an interaction between the conduction band edge and a higher‐lying band of localized nitrogen resonant states. We first present an analytical technique based on the BAC model to calculate electron energies in Ga(In)NAs square quantum well (QW) structures. We then show through detailed comparison with photoreflectance measurements that the BAC model successfully describes ground and excited state interband transition energies in bulk and QW GaNAs samples, both at ambient pressure and as a function of hydrostatic pressure. Turning to the conduction band dispersion, we find that the two‐level BAC model is insufficient, and must be modified to give a quantitative understanding of the unexpectedly large electron effective mass values observed in some GaNAs samples, which we attribute to hybridisation between the conduction band edge and nitrogen states close to the band edge. We predict a non‐monotonic variation of electron mass with hydrostatic pressure in many GaNAs samples. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)