Enhanced radiative efficiency in blue (In,Ga)N multiple-quantum-well light-emitting diodes with an electron reservoir layer

Abstract

The temperature dependence of the electroluminescence (EL) spectral intensity of two blue (In,Ga)N/GaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) without and with an additional n-doped (In,Ga)N electron reservoir layer is investigated between 20 and 300 K . The emission region of the LEDs, which have been prepared by metal-organic vapor-phase epitaxy, consists of three In 0.3Ga 0.7N QWs with a nominal width of 2.5 nm separated by 6.5 nm GaN barriers. The n-doped In 0.18Ga 0.82N electron reservoir layer has been inserted in order to exploit the effects of such additional layer on the carrier capture rates. We find that by adding the electron reservoir layer, the EL spectral intensity is significantly enhanced over a wide temperature range for a constant injection current. These results indicate the importance of the electron capture processes by radiative recombination centers in the (In,Ga)N MQW.