Design of P-Type Cladding Layers for Tunnel-Injected UVA Light Emitting Diodes

TL;DR

This paper presents the design and optimization of p-AlGaN cladding layers in tunnel-injected UV-A LEDs, demonstrating improved efficiency and novel hole injection methods for ultraviolet light emission.

Contribution

It introduces a new approach to engineer p-AlGaN layers for enhanced tunnel-injected UV LEDs and explores acceptor-free hole injection techniques.

Findings

Achieved 3.37% external quantum efficiency at 325 nm

Demonstrated acceptor-free hole injection via interband tunneling

Provided insights into hole doping and transport in AlGaN-based UV LEDs

Abstract

We discuss the engineering of p-AlGaN cladding layers for achieving efficient tunnel-injected III-Nitride ultraviolet light emitting diodes (UV LEDs) in the UV-A spectral range. We show that capacitance-voltage measurements can be used to estimate the compensation and doping in p-AlGaN layers located between the multi-quantum well region and the tunnel junction layer. By increasing the p-type doping concentration to overcome the background compensation, on-wafer external quantum efficiency and wall-plug efficiency of 3.37% and 1.62% were achieved for tunnel-injected UV LEDs emitting at 325 nm. We also show that interband tunneling hole injection can be used to realize UV LEDs without any acceptor doping. The work discussed here provides new understanding of hole doping and transport in AlGaN-based UV LEDs, and demonstrates the excellent performance of tunnel-injected LEDs for the UV-A wavelength range.