Compositionally graded AlGaN hole source layer for deep-ultraviolet nanowire light-emitting diode without electron blocking layer

Abstract

The electron blocking layer (EBL) plays a vital role in blocking the electron overflow from an active region in the AlGaN-based deep-ultraviolet light-emitting diode (DUV-LED). Besides the blocking of electron overflow, EBL reduces hole injection toward the active region. In this work, we proposed a DUV nanowire (NW) LED structure without EBL by replacing it with a compositionally continuous graded hole source layer (HSL). Our proposed graded HSL without EBL provides a better electron blocking effect and enhanced hole injection efficiency. As a result, optical power is improved by 48% and series resistance is reduced by 50% with 4.8 V threshold voltage. Moreover, graded HSL without EBL offer reduced electric field within the active region, which leads to a significant increment in radiative recombination rate and enhancement of spontaneous emission by 34% at 254 nm wavelength, as a result, 52% maximum internal quantum efficiency with 24% efficiency drop is reported.

Advantages of AlGaN Tunnel Junction in N-Polar 284 nm Ultraviolet-B Light Emitting Diode

“…37 The Mg activation energy in the p-AlGaN Hole Source Layer (HSL) was scaled linearly from 170 meV (GaN) to 670 meV (AlN). 38 A back loss value of 2400 m −1 was assumed for a 300 μm × 300 μm size LED chip. 39 In the simulation, the parameters such as Shockley Read-Hall (SRH) recombination lifetime, the Auger coefficient, and the radiative recombination coefficient were set to 10 ns, 1 × 10 −30 cm 3 s −1 , and 2.13 × 10 −11 cm 3 s −1 , respectively.…”