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

We have investigated an 850 nm GaAs/GaAlAs (001) vertical-cavity surface-emitting laser (VCSEL) structure using angle- and temperature-dependent surface photovoltage spectroscopy (SPS). The SPS measurements were performed as functions of angle of incidence (0degrees less than or equal to 0degrees less than or equal to 60degrees) and temperature (25 degreesC less than or equal to T less than or equal to 215 degrees) for both the metal-insulator-semiconductor (MIS) and wavelength-modulated MIS configurations. Angle-dependent reflectance (R) measurements have also been performed to illustrate the superior features of the SPS technique. The SPS spectra exhibit both the fundamental conduction to heavy-hole excitonic transition of quantum well and cavity mode (CM) plus a rich interference pattern related to the mirror stacks, whereas in the R spectra only the CM and interference features are clearly visible. The variations of SPS spectra as functions of incident angle and temperature enable exploration of light emission from the quantum well confined in a microcavity with relation to the Fabry-Perot cavity mode. The results demonstrate considerable potential of SPS for the contactless and nondestructive characterization of VCSEL structures.