A detailed study on optical properties of InGaN/GaN/Al2O3 multi quantum wells

In this study optical properties of InGaN/GaN/Al2O3 multi-quantum well (MQW) structures are investigated in detail. Three samples containing InGaN/GaN/Al2O3 MQWs are grown by using metal organic chemical vapor deposition technique. Sapphire (6H–Al2O3) is used as the substrate. Forbidden energy band gaps (Eg) of these three samples are determined from photoluminescence and absorption spectra. Results gained from these two spectra are compared with each other. It is found that Eg values are between 2 and 3 eV. For determining refraction index, absorption coefficients, extinction coefficients and thickness of the films a rare method called Swanepoel envelope method is used. It is seen that results gained from this method are consistent with those in literature.