Investigation of luminescence centers inside InGaN/GaN multiple quantum well over a wide range of temperature and injection currents

Abstract

InGaN/GaN multiple quantum well-based light-emitting diode LEDs were investigated over a wide range of injection currents (0.04 mA–0.1 A) and temperature (80–370 K)-dependent electroluminescence EL measurements. Two centers were identified for blue luminescence peaking at 2.9 eV and 3.0 eV, denoted as BL2 and BL$_\text {C}$, respectively. Although the 3.0 eV center was more effective than 2.9 eV under low temperature (below 160 K), both vanished completely above 170 K due to the activation of non-radiative recombination under a low-current injection regime. At the same time, EL signal intensity was significantly reduced at a high-current injection regime. The recombination through a point trap in GaN barrier layer (known as H1 trap) in InGaN/GaN multi-quantum well structure was non-radiative recombination process: this leads to either vanishing or weakening of 3.0 eV center and its energy depth were determined as 0.9 eV through temperature-dependent dc current–voltage (I–V) and ac capacitance–temperature–frequency (C–T–$\omega$) measurements. The trap depth, thermal quenching of the peak at 3.0 eV, and the sole presence of a peak at 2.9 eV at high temperature might be ascribed to carbon-related defects and agreed with recent theoretical and experimental works in literature.