Annealing effect on the electrical and optical properties of Au/n-ZnO NWs Schottky diodes white LEDs

• We studied the electrical and optical properties of Au/n-ZnO NWs Schottky diodes white LEDs.
• Devices annealed in oxygen, nitrogen and argon ambient.
• We examine the electroluminesces of devices.
• Devices show blue and red shift in the EL spectrum.
• It shows that light from the LEDs can be tuned from cold to warm light by post growth annealing.

We report the post-growth heat treatment effect on the electrical and the optical properties of hydrothermally grown zinc oxide (ZnO) nanowires (NWs) Schottky white light emitting diodes (LEDs). It was found that there is a changed in the electroluminescence (EL) spectrum when post growth annealing process was performed at 600 °C under nitrogen, oxygen and argon ambients. The EL spectrum for LEDs based on the as grown NWs show three bands red, green and blue centered at 724, 518 and 450 nm respectively. All devices based on ZnO NWs annealed in oxygen (O2), nitrogen (N2) and argon (Ar) ambient show blue shift in the violet and the red emissions whereas a red shift is observed in the green emission compared to the as grown NWs based device. The color rendering index (CRI) and the correlated color temperature (CCT) of all LEDs were calculated to be in the range 78–91 and 2753–5122 K, respectively. These results indicate that light from the LEDs can be tuned from cold white light to warm white light by post growth annealing.