Manipulation on the optical properties of InGaN/GaN light emitting diodes by adopting InN layer

We report the influence of an InN layer inserted between InGaN and GaN on the optical properties of InGaN/GaN light emitting diode (LED). The emission wavelength of the InGaN/GaN LED with the InN layer was 459 nm at 10 K, which was red-shifted by 6 nm from that of the LED without the insertion layer (reference LED). The peak position of the reference LED subjected to thermal treatment at 825°C was blue-shifted by 3.5 nm compared to that of the as-grown sample due to the structural variation of indium (In)-related features in InGaN/GaN quantum wells (QWs) and inter-diffusion of In and gallium (Ga) at the interface. However, the emission peak for the InGaN/GaN LED with the InN layer was red-shifted with increasing annealing temperatures. This result can be explained by the additional introduction of In to InGaN/GaN QWs and the reduction in the probability for Ga atoms at the GaN barrier to diffuse into InGaN through the InN layer.