Color tunable light-emitting diodes based on p+-Si/p -CuAlO2 /n-ZnO nanorod array heterojunctions

Abstract

Wide-range color tuning from red to blue was achieved in phosphor-free p+ -Si/p -CuAlO2 /n-ZnO nanorod light-emitting diodes at room temperature. CuAlO2 films were deposited on p+ -Si substrates by sputtering followed by annealing. ZnO nanorods were further grown on the annealed p+ -Si/p -CuAlO2 substrates by vapor phase transport. The color of the p -CuAlO2 /n-ZnO nanorod array heterojunction electroluminescence depended on the annealing temperature of the CuAlO 2 film. With the increase of the annealing temperature from 900 to 1050°C, the emission showed a blueshift under the same forward bias. The origin of the blueshift is related to the amount of Cu concentration diffused into ZnO. © 2010 American Institute of Physics.