Abstract
Despite the fact that an InGaN/GaN superlattice (SL) is useful for enhancing the performance of a GaN-based light-emitting diode (LED), its role in improving the efficiency of green LEDs remains an open question. Here, we investigate the influence of a V-pits-embedded InGaN/GaN SL on optical and electrical properties of GaN-based green LEDs. We recorded a sequence of light emission properties of InGaN/GaN multiple quantum wells (MQWs) grown on a 0- and 24-pair InGaN/GaN SL by using scanning electron microscopy (SEM) in combination with a room temperature cathodoluminescence (CL) measurement, which demonstrated the presence of a potential barrier formed by the V-pits around threading dislocations (TDs). We find that an increase in V-pit diameter would lead to the increase of V-pit potential barrier height. Our experimental data suggest that a V-pits-embedded, 24-pair InGaN/GaN SL can effectively suppress the lateral diffusion of carriers into non-recombination centers. As a result, the external quantum efficiency (EQE) of green LEDs is improved by 29.6% at an injection current of 20 mA after implementing the V-pits-embedded InGaN/GaN SL layer. In addition, a lower reverse leakage current was achieved with larger V-pits.
Highlights
GaN-based light-emitting diodes (LEDs) have been applied in many commercial areas, such as backlights for liquid crystal displays (LCDs), solid-state lighting, visible light communications, head-up displays, and optogenetics [1,2,3,4,5,6,7]
It has been reported that the “green gap” is caused by high-density threading dislocations (TDs), which result from a large mismatch in the lattice parameter between the GaN and the high-In-content InGaN
Previous studies have demonstrated that the V-pits could impact the performance of LEDs, such as the leakage current, electrostatic discharge capabilities, and the radiative recombination efficiency [24,25,26,27]
Summary
GaN-based light-emitting diodes (LEDs) have been applied in many commercial areas, such as backlights for liquid crystal displays (LCDs), solid-state lighting, visible light communications, head-up displays, and optogenetics [1,2,3,4,5,6,7]. Previous studies have demonstrated that the V-pits could impact the performance of LEDs, such as the leakage current, electrostatic discharge capabilities, and the radiative recombination efficiency [24,25,26,27].
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