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Photoreflectance studies of (Al, Ga)As/GaAs heterostructures and devices
Author(s) -
Enderlein Rolf
Publication year - 1996
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.2221940124
Subject(s) - heterojunction , spectral line , mesfet , quantum well , dopant , materials science , condensed matter physics , physics , molecular physics , optoelectronics , computational physics , optics , quantum mechanics , doping , field effect transistor , transistor , laser , voltage
Experimental and theoretical PR spectra are reported for (AlGa)As/GaAs single heterostructures, (AlGa)As/GaAs quantum well structures as well as MESFET and HEMT structures. The theoretical spectra are calculated by means of a novel technique which combines the two methods previously used for spatially inhomogeneous systems: the transfer matrix method for light propagation between different layers, and perturbation theory for light propagation within each weakly inhomogeneous layer. The electric field distribution is calculated from an integral equation which holds under quite general conditions including incomplete dopant ionizations and carrier degeneracies. In most of the spectra, pronounced interference effects show up. Due to them, PR spectra from quantum wells are sensitive to the well distance from the surface. Besides interference effects, field inhomogeneities like broadening of Franz‐Keldysh oscillations manifest themselves in the reported spectra. A controversy in the literature concerning PR spectra from (AlGa)As/GaAs single heterostructures is solved by means of the novel calculation technique.