Reflective metal/semiconductor tunnel junctions for hole injection in AlGaN UV LEDs


Zhang Y., Krishnamoorthy S., Akyol F. , Johnson J. M. , ALLERMAN A. A. , MOSELEY M. W. , ...More

APPLIED PHYSICS LETTERS, vol.111, no.5, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 111 Issue: 5
  • Publication Date: 2017
  • Doi Number: 10.1063/1.4997328
  • Title of Journal : APPLIED PHYSICS LETTERS

Abstract

In this work, we investigate the use of nanoscale polarization engineering to achieve efficient hole injection from metals to ultra-wide bandgap AlGaN, and we show that UV-reflective aluminum (Al) layers can be used for hole injection into p-AlGaN. The dependence of tunneling on the work function of the metal was investigated, and it was found that highly reflective Al metal layers can enable efficient hole injection into p-AlGaN, despite the relatively low work function of Al. Efficient tunneling hole injection was confirmed by light emission at 326 nm with an on-wafer peak external quantum efficiency and a wall-plug efficiency of 2.43% and 1.33%, respectively. A high power density of 79.0 W/cm(2) was measured at 1200 A/cm(2). The metal/semiconductor tunnel junction structure demonstrated here could provide significant advantages for efficient and manufacturable device topologies for high power UV emitters. Published by AIP Publishing.