Nitride-based light-emitting diodes with InGaN/GaN SAQD active layers

InGaN/GaN blue light-emitting diodes (LEDs) with self-assembled quantum dot (SAQD) active layers were successfully fabricated using an interrupted growth method in metal-organic chemical vapour deposition (MOCVD). Nanoscale QDs have been formed successfully embedded in quantum wells (QWs) with a typical 3 nm height and 10 nm lateral dimension. A huge 68.4 meV blue shift in electroluminescence (EL) peak position was found as the injection current was increased from 3 to 50 mA for the SAQD LED. The large EL blue shift reveals that deep localisation of exitons (or carriers) originating from QDs strengthens the band-filling effect as the injection current increases.