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

Abstract

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 (0° ≤ θ ≤ 60°) and temperature (25° C ≤ T ≤ 215° C) 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–Pérot cavity mode. The results demonstrate considerable potential of SPS for the contactless and nondestructive characterization of VCSEL structures.

A vector model for analysing the surface photovoltage amplitude and phase spectra applied to complicated nanostructures

“…However, there are still open questions in the analysis of the results obtained by the MIS technique. Usually, only the SPV amplitude spectrum is considered in the literature [10][11][12][13][14][15] and little attention is paid to the information that can be retrieved from the SPV phase spectrum. The SPV phase spectra have been discussed mainly in terms of relative changes 1 Author to whom any correspondence should be addressed.…”

Surface photovoltage phase spectroscopy study of the photo-induced charge carrier properties of TiO2 nanotube arrays

“…In a study of nano-scale TiO 2 electrodes using the SPV technique, Wang et al [8] found that when modified with PbS, the surface states of TiO 2 are greatly suppressed; Jing et al [9] found that on the surface of a n-TiO 2 /Ti film, the amount of Ti 3+ surface states is low or non-existent and the SPV response is possibly related to the surface states resulting from the surface hydroxyl groups; Qian et al [10] reported that TiO 2 nanoparticles prepared from basic sols have more defects than those prepared from acidic sols and the incorporation of CdS can decrease the surface state density on TiO 2 electrodes. In this type of SPV technique, usually only the SPV amplitude spectrum has been considered in the literature [8][9][10][11][12][13][14][15], and little attention has been paid to the information in the SPV phase spectrum. In some reports [16,17], the SPV phase spectrum has been discussed, but just as a complement of the SPV amplitude spectrum.…”