Surface photovoltage spectroscopy as a valuable nondestructive characterizationtechnique for GaAs/GaAlAs vertical-cavity surface-emitting laser structures

Abstract

We have investigated an 850 nm GaAs/GaAlAs (001) vertical-cavity surface-emittinglaser (VCSEL) structure using angle- and temperature-dependent surfacephotovoltage spectroscopy (SPS). The SPS measurements were performed asfunctions of angle of incidence (0° ≤ θ ≤ 60°)and temperature (25° C ≤ T ≤ 215° C)for both the metal–insulator–semiconductor (MIS) andwavelength-modulated MIS configurations. Angle-dependent reflectance(R)measurements have also been performed to illustrate the superior features of theSPS technique. The SPS spectra exhibit both the fundamental conduction toheavy-hole excitonic transition of quantum well and cavity mode (CM) plusa rich interference pattern related to the mirror stacks, whereas in theRspectra only the CM and interference features are clearly visible. The variations ofSPS spectra as functions of incident angle and temperature enable exploration oflight emission from the quantum well confined in a microcavity with relation tothe Fabry–Pérot cavity mode. The results demonstrate considerable potential ofSPS for the contactless and nondestructive characterization of VCSEL structures.