InGaN/AlGaInN-based ultraviolet light-emitting diodes with indium gallium tin oxide electrodes

• Indium gallium tin oxide (IGTO) for near-ultraviolet light-emitting diode is proposed.
• IGTO is fabricated by co-sputtering the ITO and Ga2O3 targets and hydrogen annealing.
• IGTO shows a 94% transmittance at 385 nm and a 9.4 × 10− 3 Ω-cm2 contact resistance.
• Near-ultraviolet light-emitting diode with IGTO shows improved optical performance.

In this study, In- and Sn-doped GaO (IGTO) is proposed as an alternative transparent conductive electrode for indium tin oxide (ITO) to improve the performance of InGaN/AlGaInN-based near ultraviolet light-emitting diodes (NUV LEDs). IGTO films were prepared by co-sputtering the ITO and Ga2O3 targets under various target power ratios. Among those, IGTO films post-annealed at 700 °C under a hydrogen environment gave rise to a transmittance of 94% at 385 nm and a contact resistance of 9.4 × 10− 3 Ω-cm2 with a sheet resistance of 124 Ω/ϒ. Compared to ITO-based NUV LEDs, the IGTO-based NUV LED showed a 9% improvement in the light output power, probably due to IGTO's higher transmittance, although the forward voltage was still higher by 0.23 V.