Abstract
Gallium Nitride (GaN) based light-emitting diodes (LEDs) are being utilized in an ever expanding number of applications. The persistent issues, however, have been the use of alternating current (AC) to direct current (DC) converters and the inefficient p-type doping compared to n-type doping. Here, a novel hybrid AC InGaN quantum well (QW) LED without a p-GaN layer is demonstrated at 450 nm. A tunneling LED is fabricated through use of InGaN QWs, combined with a thin Al2O3 dielectric with NiO as the source of the holes. This hybrid InGaN LED utilizes Fowler-Nordheim tunneling and band bending in order to inject holes into the active region. Due to the symmetric nature of the tunneling, hole or electron injection through the top oxide layer leads to AC performance. Room temperature and cryogenic I-V measurements are performed to evaluate the tunneling mechanism. Tunneling of holes is found to lead to earlier device turn-on of ~0.5 V compared with conventional blue LEDs at ~2 V. The presented work can lead to a number of novel applications such as on-chip communication, monolithic integration with transistors, and LiFi.
Highlights
Leds provide efficient solid-state lighting for homes, businesses, and display technology [1]–[4]
For our proposed tunneling Gallium Nitride (GaN) alternating current (AC) light-emitting diodes (LEDs), holes are provided by a metal film stack and the formation of NiO, which together act as a source of both excess holes and electrons
A novel tunneling GaN LED was presented. This device makes use of band bending and carrier tunneling in order to inject holes directly into the multiple quantum well (MQW) region
Summary
Leds provide efficient solid-state lighting for homes, businesses, and display technology [1]–[4]. For our proposed tunneling GaN AC LED, holes are provided by a metal film stack and the formation of NiO, which together act as a source of both excess holes and electrons. Use of NiO provides a better source of high density holes over other works with attempt to employ heavily doped GaN p-n junctions [15] In this work, a Ti/Al/Ni/Ag metal film stack and a 50 nm Al2O3 dielectric film were used. Both the dielectric and metal stack were chosen due to the prevalence in GaN power devices to allow for potential integration. A novel introduction of AC functionality is demonstrated from the tunneling GaN LED in this work
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