The action of silicon doping in the first two to five barriers of eight periods In0.2Ga0.8N/GaN multiple quantum wells of blue LEDs

Abstract

First two to five barriers in the growth sequence having silicon (Si) doping of eight periods In0.2Ga0.8N/GaN quantum wells (QWs) on twenty pairs of In0.02Ga0.98N/GaN superlattice strain relief layers (SRLs) of blue LEDs were prepared by low pressure metal–organic chemical vapor deposition (LPMOCVD) system on patterned sapphire substrates (PSSs). The effect of doping layers on the luminescence properties of QWs of blue LEDs was investigated. For the sample with first four barriers having Si doping, formation of soft confinement of QWs potential and strong carrier localization inside QWs were occurred. There is better spread of carriers among eight QWs and strong radiative recombination of carriers inside QWs. The increase of output power and external quantum efficiency (EQE) is due to decrease of Auger processes, leakage of carriers out of QWs, and nonradiative recombination centers. The consequences demonstrate that first four barriers with Si doping possess the favorable doping condition for eight periods In0.2Ga0.8N/GaN QWs.