Time resolved spectra study of GaN light emitting diodes (LEDs)

Abstract

We study time-resolved-spectra of InGaN and GaN diodes with a short electrical pulse. LEDs with four different structures were studied: the bulk InGaN/GaN blue LED (/spl lambda//sub peak/ = 450 nm); the InGaN single quantum well (SQW) blue LED (/spl lambda//sub peak/ = 470 nm); the InGaN SQW green LED (/spl lambda//sub peak/ = 525 nm); and the Zn disordered GaN active layer (/spl lambda//sub peak/ = 430 nm). When pumped with short electrical pulses, some of them can generate UV light. The electrical pump time-resolved spectrum studies provide a convenient tool to investigate the recombination process in the GaN material system. The results show that the UV emissions from bulk GaN and bulk InGaN materials, and the blue as well as the green emissions from the high efficiency InGaN SQW LEDs, correspond to bandedge transitions.