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Complex dielectric function of AlGaN/GaN/InGaN heterojunction structures
Author(s) -
Jogai B.
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.200301952
Subject(s) - heterojunction , optoelectronics , materials science , dielectric , quantum well , piezoelectricity , electric field , condensed matter physics , valence band , fermi gas , electron , band gap , optics , physics , composite material , laser , quantum mechanics
Theoretical calculations of the complex dielectric function of AlGaN/GaN heterojunction field‐effect transistor (HFETs) structures and InGaN/GaN single quantum wells (SQWs) are presented. The model is based on a self‐consistent calculation of the band structure, taking into account the spontaneous and piezoelectric polarizations and the presence of a two‐dimensional electron gas (2DEG) at the interface. The calculated results show that the large built‐in electric field at the heterojunction smears out any fine structures in the dielectric function that would ordinarily be expected from transitions between the valence band edge and the confined electron states. For HFET structures, two broad features are seen in the calculated spectra, one due to the GaN layer and the other to the AlGaN barrier. There are no features due to the confined states in the 2DEG. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)