Transparent conductive Ga-doped ZnO (ZnO:Ga) was fabricated to serve as p-contacts of InGaN-based light-emitting diodes (LEDs) using molecular-beam epitaxy. As-grown ZnO:Ga films typically have resistivities of ρ = 2 - 4 × 10-4 Ω-cm, and over 80% transparency in the near UV and visible wavelength ranges. The current-voltage characteristics between as-grown ZnO:Ga contacts and p-GaN layers were ohmic. The brightness of LEDs fabricated with ZnO:Ga p-contacts was nearly double compared to LEDs with conventional Ni/Au p-contacts. We obtained the external efficiency as high as 20.8% in the case of the near UV LED. The forward voltage at 20mA was found not to increase even after the lamp LED with ZnO:Ga were kept for 80h in high humidity and high temperature environments.
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Issue number||2 A|
|Publication status||Published - 2004 Feb 1|
- External efficiency
- Ohmic contact
ASJC Scopus subject areas
- Physics and Astronomy(all)