Ultraviolet electroluminescence in AlN

Abstract

A method of growing single-crystal low-resistivity (∼103 Ω cm) n-type AlN is described in which dc ultraviolet electroluminescence is observed for the first time. The emission is in a broad band extending from 215 nm into the blue end of the visible spectrum. AlN grown on tungsten and sapphire substrates is contacted with Al and Nb. Light emission occurs in small spots near the negatively biased contact for currents of a few mA at voltages as low as 17 V, but typically in the range between 30 and 150 V. The external quantum efficiency is 6×10-6, and at constant current the light output is nearly independent of temperature up to several hundred degrees centigrade.