Influence of electrodes layout on hydrothermally-grown GaN/ZnO LEDs

Light-emitting diodes (LEDs) based on zinc oxide, with wide direct band gap, have drawn much attention in the last years. ZnO, which is natural n-type, has excellent physical and chemical properties, is inexpensive, abundant and nontoxic. Unfortunately, the preparation of reproducible and high quality p-type ZnO film is comparatively difficult, due to the low solubility of acceptor dopants, self-compensating effects, and acceptor level energy height. Although many groups have reported on ZnO-based homostructure LEDs, the results are controversial as recently reviewed in [1]. Hence, heterojunction LEDs based on ZnO as the nside and GaN as the p-side of the junction have been put forward [2].…