Investigation of robust bandgap semiconductor structures using optical spectroscopy methods

In the paper we show and discuss the utilization of different optical spectroscopy methods such as photoluminescence or μ-Raman microscopy with UV or VIS excitation to analysis of robust bandgap materials properties particularly GaN and ZnO based structures. These techniques are capable to discover tiny changes in material properties induced by variety of influences such as material composition, doping, strain or temperature. The measurements of Raman spectra of annealed ZnO/GaP at different temperatures revealed that the structure annealed at 340°C show considerable changes in Raman spectra due to re-crystallization. The calibration measurements of Raman and PL temperature shift were done for AlGaN/GaN high electron mobility transistor (HEMT) structure with the aim to investigate the temperature distribution inside the HEMTs channel.