A phosphor-free white light-emitting diode using In₂O ₃: Tb transparent conductive light converter

Tb-doped indium oxide (In₂O₃ : Tb) films were deposited on a GaN-based near-ultraviolet (NUV) light-emitting diode (LED) as a transparent conductive light converter to form a white LED. The transmittance of the In₂O₃ : Tb film (Tb at 10 wt%) exceeded 80% in visible light and the resistivity was 0.325 Ω cm. The In₂O ₃ : Tb transparent conductive light converter was also employed on GaN-based LEDs. GaN-based NUV-LEDs with In₂O₃ : Tb film (Tb at 10 wt%) produced forward biases of 3.42 V at an injection current of 20 mA. With increasing temperature, increasing Tb³⁺ concentration and increasing injection current from 20 to 100 mA, the chromaticity coordinates barely changed in the white light area. Therefore, the GaN-based NUV-LED with In₂O₃ : Tb film had a stable white light colour, when temperature and injection current changed, and is suitable for solid-state lighting.