Raman study of band bending at ZnSe/GaAs interfaces

Abstract

Apparent p-type conductivity in nonintentionally doped ZnSe layers, grown at high temperature on semi-insulating GaAs substrates, is investigated by Raman spectroscopy. The microprobe technique provides direct evidence for carrier location on the GaAs side of the structures, close to the interface. Line-shape analysis of the coupled LO phonon-plasmon mode for different exciting wavelengths can be achieved, within the model of Hon and Faust [Appl. Phys. 1, 241 (1973)], only when incorporating plasma inhomogeneity. Electronic band bending at the junction in GaAs is deduced from the inferred carrier-density profile. Changes in Raman spectra under strong illumination are shown to proceed from the flattening of the bands through selective carrier photoinjection. © 1995 American Institute of Physics.