Surface photovoltage spectroscopy characterization of AlGaAs/GaAs laser structures

The characterization of AlGaAs/GaAs laser structures using surface photovoltage spectroscopy (SPS) is presented. The experiments were carried out at room temperature in the simplified variant of metal–insulator–semiconductor (MIS) configuration by means of a lab-made automated experimental setup. With this technique was possible to identify all the layers forming the heterostructure and important parameters have been extracted. The aluminium composition of the layers, obtained in this way agrees very well with the intentional growth parameters. Also from the surface photovoltage spectra was possible to obtain the lasing wavelength in each structure, which is in a good agreement with the values obtained by measuring the electroluminescence spectra. Results underline the power of SPS in characterization of actual laser devices in a contactless nondestructive way.