Role of electron leakage on efficiency droop in AlxGa(1−x)N/GaN ultraviolet LEDs

Abstract

Highly efficient AlxGa1−xN/GaN deep ultraviolet LEDs are widely used for water purification and medical diagnostics. However, these LEDs undergo efficiency reduction problem known as efficiency droop. Many causes of efficiency droop have been found; out of these one strong cause is electron leakage (EL). Electrons are leaked from the active region of the device before recombination. Electron leakage in AlxGa1−xN/GaN deep ultraviolet LEDs depends on temperature and carrier concentration. Here we investigate efficiency droop phenomenon of AlxGa1−xN/GaN deep ultraviolet LEDs under the effect of polarization charges on carrier concentrations. It is found that efficiency is decreased when polarization and applied current increases.