Growth and characterization of InGaN quantum dots in InGaN/GaN superlattices

The growth mode changing from two-dimensional to three-dimensional is promising in enhancing the efficiency of optical devices, such as light emitting diodes and laser. Thus, InCaN/GaN superlattice structures were grown on sapphire by metalorganic chemical vapor deposition. Transmission electron microscope was used to obtain cross-sectional images of the samples. For the analysis of the layer structure, the ω -scans and rocking curves of x-ray diffraction were employed to examine strain, misorientation and periodicity of the supperlattice. The property of the origin of luminescence in the InGaN/GaN multiple quantum wells was determined by photoluminescence. The results show that high quality InGaN quantum dots in supperlattices are achieved, where the average size is 1-2 nm and the density is 9×10¹² cm ^-2. The emitting wavelength can be varied by changing the growth rate for the active layers.