Dry-etch damage and its recovery in InGaN/GaN multi-quantum-well light-emitting diodes

Abstract

Etch-induced damage in GaN/InGaN multi-quantum well light-emitting diodes (LEDs) caused by a Cl 2 -base plasma and its recovery by means of a N 2 -plasma and annealing process of n-GaN is described. The photoluminescence intensity of etched n-type GaN was decreased by several orders of magnitude due to etch-induced damage, giving rise to an increase in the leakage current in LED current-voltage curves. However, treatment of the LEDs with a N 2 plasma along with a rapid thermal annealing process led to an enhancement in the I -V characteristics of the LEDs due to the suppression of the leakage current. The electroluminescence intensity of LEDs which was etched at dc bias of −200 V was also improved by a factor of two relative to the as-etched LEDs, as a result of this treatment.

InGaN/GaN nanopillar‐array light emitting diodes

“…All electrical characterization was performed on a Tektronix 370A curve tracer at room temperature and optical measurements were made through the substrate. Current-Voltage (I-V) measurements showed rectifying behavior and a turn-on voltage of approximately 3 V, series resistance of 53 Ω, and reverse bias leakage of 2.1 mA @ -5 V. The large reverse bias leakage may be attributed to surface damage during pillar etching as has been reported in the literature [12]. This effect causes considerable leakage in our devices due to the large surface area of our structures, and surface passivation techniques will be used in the future in attempts to reduce the effects of etch damage.…”

Crystallographic Wet Chemical Etching of Semipolar GaN (11–22) Grown on <I>m</I>-Plane Sapphire Substrates

“…Figure 1(a) shows the XRD pattern of semipolar GaN with thickness of 2 m for X-ray incident toward the direction. The surface orientation of the sample was confirmed to be (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN. Figure 1(b) shows a schematic diagram of the direction, such as (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN on m-plane sapphire.…”

Enhanced Cathodoluminescence of KOH-treated InGaN/GaN LEDs with Deep Nano-Hole Arrays

“…These result in a degradation of the electrical and optical characteristics of the InGaN/GaN LED. It is known that the plasma-induced damages on the surfaces may be recovered by annealing or chemical treatments [9,10,18]. In this study, we investigate the effect of KOH wet chemical treatment on the luminescence properties of the e-beam nano-patterned InGaN/GaN LED, especially when the nano-patterns penetrate into the MQWs.…”

“…Theoretically, the higher light extraction efficiency of the LED is expected from the deeper photonic crystal pattern regardless of the bandgap or the non-bandgap structures [8]. However, the experimental results reveal that light emission intensity is usually reduced when the etchedpatterns penetrate into the MQW active layer due to the plasma-induced damage [9,10]. Therefore, most of the studies using photonic crystal for the InGaN/GaN LEDs focus on the patterning just on their top p-GaN layer.…”