Improved efficiency of InGaN/GaN light-emitting diodes with Al-doped zinc oxide using dual-plasma-enhanced metal-organic chemical vapour deposition system

We have reported aluminium doped zinc oxide (AZO) film grown on sapphire substrate using dual-plasma-enhanced metal-organic chemical vapour deposition (DPEMOCVD) system. The crystalline quality, surface morphology, optical properties, and electrical characteristic of AZO film depend on the deposition temperature and Al content. The 185°C-deposited and 2.88 at%-Al-doped AZO film shows a strong (002) diffraction peak intensity, flat surface morphology, high transmittance in visible range, and low resistivity. The PL peak of AZO film shows a blue-shift as compared to undoped ZnO film due to the Burstein-Moss (BM) effect. Finally, the AZO film was deposited on InGaN/GaN light-emitting diodes (LEDs) as transparent conductive layer (TCL). InGaN/GaN LED with optimal AZO TCL shows the lowest dynamic resistance, highest light output intensity, and narrowest full-width at half-maximum (FWHM) emitting spectrum as compared to those without TCL and with indium-tin-oxide (ITO).