Improving hole injection in deep UV LEDs

Researchers based in Wuhan, China, report improved light output power (LOP) and operating voltages for deep ultraviolet (DUV) light-emitting diodes (LEDs) from reducing carbon (C) impurities in the p-type layers [Ziqi Zhang et al, Appl. Phys. Lett., v125, p241109, 2024].

The C impurity comes from the metal-organic (MO) precursors used in the chemical vapor deposition (CVD) aluminium gallium nitride (AlGaN) growth process used to create DUV LED material.

The reduced C content was effected by slowing the growth rate of the AlGaN. In particular, the C content was reduced in the electron-blocking layers (EBLs) and graded p-AlGaN layers, allowing higher Al content. EBLs are critical for reducing electrons from penetrating into the p-type layers.