Optical Improvement of GaN-Based Light Emitting Diodes by Interfacial Si Treatment in InGaN/GaN Quantum Well Structure

We investigated the optical enhancement of GaN-based light-emitting diodes (LEDs) by introducing Si treatment at the interface between the well and the barrier. The results of X-ray diffraction showed that the interfacial quality of InGaN/GaN quantum wells was slightly degraded by interfacial Si treatment. However, the intensities and full width at half-maximums (FWHMs) of photoluminescence (PL) and electroluminescence (EL) were increased by introducing interfacial Si treatment. In addition, the efficiency droop of the reference LED was 34.2% at 50 mA, while that of the Si-treated LED was 26.7% at 50 mA. Despite the increase in EL intensity, the efficiency droop was significantly decreased by interfacial Si treatment. From these results, we believe that the interfacial Si treatment will induce appropriate In localization in the InGaN active region, resulting in the improvement of optical quality of LEDs. (C) 2012 The Japan Society of Applied Physics