Indium tin oxide contacts to gallium nitride optoelectronic devices

Abstract

We have fabricated GaN-based light-emitting diodes using transparent indium tin oxide (ITO) p contacts. ITO-contacted devices required an additional 2 V to drive 10 mA, as compared to similar devices with metal contacts. However, ITO has lower optical absorption at 420 nm $\text{(α=664\hspace{0.5em}}{\mathrm{cm}}^{\mathrm{-1}})$ than commonly used thin metal films ${\text{(α=3×10}}^5\hspace{0.5em}{\mathrm{cm}}^{\mathrm{-1}}\mathrm{).}$ Uniform luminescence was observed in ITO-contacted devices, indicating effective hole injection and current spreading.