Cross sections for the investigation of the electroluminescence excitation of InGaN∕GaN quantum wells in blue light-emitting diodes with multiquantum barriers

Abstract

Cross sections of the electroluminescence (EL) excitation of InGaN∕GaN multiquantum wells (MQWs) in blue light-emitting diodes (LEDs) with multiquantum barriers (MQBs) have been investigated. It was found that a device with an MQB structure exhibited a higher quantum efficiency, as well as higher temperature insensitivity, compared with the conventional MQW LEDs. A total cross section of 5.3×10−15cm2 was obtained for the MQB QWs, by fitting them to the measurement of the spectral intensity at room temperature; the value was 4.5×10−15cm2 for those devices with GaN barriers. Not only the EL excitation cross section for active region, but also the abnormal quantum efficiency evolutions were found to be a function of temperature. Moreover, they were in good agreement with the rate equation model.