The effect of growth temperature on structural quality of AlInGaN/AlN/GaN heterostructures grown by MOCVD

In this paper, the influence of the growth temperature on the structural quality of AlInGaN epilayer on the GaN/sapphire substrate grown by metal–organic chemical vapor deposition has been studied. The AlInGaN epilayers has been characterized by high-resolution X-ray diffractometer, atomic force microscopy, photoluminescence spectra and Raman scattering spectrometer. The growth temperature is believed to have a direct influence on the quality of the AlInGaN epilayer. Upon optimizing the growth temperature, at 890 °C a high crystalline quality with a full width at half maxima for the (0004) and (10–15) planes are 312 and 618 arc-sec, respectively has been achieved. It has been found that the number of V-defect pits at high growth temperature can be minimized. The AlInGaN also revealed atomic level step with a root mean square roughness of 0.13 nm. Other than the AlInGaN related room temperature photoluminescence peak, two emissions originate from InGaN-like clusters and the AlInGaN random matrix, respectively. In the Raman spectra, the mode at 748 cm⁻¹ is attributed to the A₁ (LO) mode of AlInGaN. The mode at 680 cm⁻¹ is attributed to InGaN clustering and assigned as A₁ (LO) mode.