Direct Measurement of Auger Electrons Emitted from a Semiconductor Light-Emitting Diode under Electrical Injection: Identification of the Dominant Mechanism for Efficiency Droop

摘要

We report on the unambiguous detection of Auger electrons by electronemission spectroscopy from a cesiated InGaN/GaN light emitting diode (LED)under electrical injection. Electron emission spectra were measured as afunction of the current injected in the device. The appearance of high energyelectron peaks simultaneously with an observed drop in electroluminescenceefficiency shows that hot carriers are being generated in the active region(InGaN quantum wells) by an Auger process. A linear correlation was measuredbetween the high energy emitted electron current and the "droop current" - themissing component of the injected current for light emission. We conclude thatthe droop phenomenon in GaN LED originates from the excitation of Augerprocesses.