Polarized edge-incident photovoltage spectroscopy and reflectance characterization of a GaAs/GaAlAs vertical-cavity surface-emitting laser structure

Abstract

Polarized edge-incident photovoltage spectroscopy (EPVS) and normal-incident reflectance (NIR) studies are performed at room temperature on a bare as-grown wafer of GaAs/GaAlAs-based vertical-cavity surface-emitting laser (VCSEL) structure, designed for emitting at a wavelength near 850 nm. In addition to the interference features related to the properties of the mirrors stacks, in the NIR spectrum only the Fabry–Pérot cavity mode is clearly visible, while the polarized EPV spectra are used to identify the wavelength of fundamental and higher-order transitions from the quantum wells (QWs) in the active region. By comparing the experimental results with theoretical calculations, we are able to ascertain the Al composition, structure parameters, and material quality of the QWs in the VCSEL active regions. We demonstrate the potential of polarized EPVS for the contactless and nondestructive characterization of VCSELs at room temperature.