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).

Keywords: aluminium doped doped zinc oxide, AZO, ZnO, dual–plasma–enhanced metal–organic CVD, chemical vapour deposition, InGaN/, GaN LEDs, light–emitting diodes, nanoelectronics, nanotechnology, sapphire substrate, deposition temperature, crystalline quality, surface morphology, optical properties, electrical characteristics, indium gallium nitride