Improvement of light extraction and carrier injection in far UV-C LEDs on AlN substrate via conductive p-Al0.45Ga0.55N contact layer

Abstract

In this study, we report the application of a p-Al0.45Ga0.55N contact layer in far ultraviolet-C light-emitting diodes (LEDs) on AlN substrates to enhance wall-plug efficiency (WPE). The LEDs achieved an optical power of 9.3 mW and a voltage of 6.4 V at 100 mA current, corresponding to a 1.7-fold improvement in WPE (1.4%) compared to conventional p-GaN-based LEDs. Lifetime tests suggest that this efficiency gain arises from both light extraction and carrier injection. Finally, Hall-effect measurements of bulk Mg-doped Al0.45Ga0.55N demonstrated low resistivity, small activation energy, and inverted carrier type.