JOURNAL OF MATERIALS SCIENCE: MATERIALS IN ELECTRONICS, cilt.00, sa.00, 2022 (SCI-Expanded)
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 BLC, 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–x) 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.