Fabrication and characterization of n-ZnO nanorod/p-CuAlO2 heterojunction

n-ZnO nanorod/p-CuAlO₂ heterojunction diodes have been fabricated on p⁺-Si (100) substrates. The p-CuAlO₂ thin films were deposited on Si substrates by DC-sputtering method and then n-ZnO nanorods were grown by vapor phase transport (VPT) system on the CuAlO₂ layer. The well aligned ZnO nanorods show single wurtzite hexagonal structure. Current-voltage characterization of the heterojunction exhibits rectifying diode behavior with a turn-on voltage of about 4.5 V. Electroluminescence emission, involving a weak near-band-edge emission of ZnO at 380 nm and a strong deep-level emission at 550 nm were observed at room temperature from the diode under forward bias.