INVESTIGATION OF THE INDIUM ATOM INTERDIFFUSION ON THE GROWTH OF GAN INGAN HETEROSTRUCTURES/

The influence of the growth procedure on the optical quality of InGaN grown on GaN has been investigated. The photoluminescence spectrum of the sample with a low-temperature-grown GaN cap layer or a graded-temp erature-grown GaN cap layer has a shorter peak wavelength than that of the sample grown with a normal-temperature-grown GaN layer. The shift of the peak wavelength increases with the increase of the layer thick ness for the sample with the low-temperature-gown GaN. This is because the defects contained in the low-temperature-grown GaN cap layer indu ce the outdiffusion of In atoms during the temperature-ramped procedur e. The narrower linewidths and higher intensities of the PL spectra fo r InGaN after In outdiffusion may be due to the reduction of the strai ns, dislocations or defects. The Raman spectra and the Auger electron spectra also indicate that the low-temperature-grown GaN has a lot of defects which reduce the phonon peak intensity and induce the interdif fusion of In atom during the growth of GaN/InGaN heterostructures.