Effect of Interface Microrelief on Optical, Electrical and Photoelectric Characteristics of Heteroepitaxial AlxGa1-xAs/GaAs Structures

We have investigated the dependence of optical, photoelectric and electrical characteristics of heteroepitaxial Al
_x
Ga
_1-x
As/GaAs structures on active interface microrelief morphology. Experimental study of heterostructures included analysis of surface microrelief parameters by AFM techniques, measurements of specular and diffuse reflection spectra, the dark and light current-voltage (I-V) characteristics and spectra of the short-circuit photocurrent. Investigation showed that advantages of optical and recombination properties of an anisotropically etched GaAs surface may be remained in Al
_x
Ga
_1-x
As/GaAs heterostructures at a suitable choice of processing regimes. To explain reduction of the open circuit voltage (V
_OC
) in some heterostructures with textured interface a theoretical analysis has been made for V
_OC
dependence on the nonuniformity of doping with impurity atoms caused by interface roughness