Near-ultraviolet light-emitting diodes realized from n-ZnO nanorod/p-GaN direct-bonding heterostructures

Reproducible near-ultraviolet (near-UV) light-emitting diodes composed of ZnO nanorods (NRs) and p-GaN film using direct-bonding (DB) structure have been demonstrated and characterized. It is revealed that numerous p–n heterojunctions are formed between the ZnO NR top tips and GaN film after the thermal treatment. Dominant near-UV electroluminescence (EL) centered at 400 nm was observed and green–orange defect-related light emissions were absent, which is probably due to the formation of high-quality p–n heterojunctions where the EL is stimulated. The EL origination and related carrier transport mechanism were discussed qualitatively in terms of photoluminescence results and energy band diagram. Itʹs hoped that the DB structure may serve as a feasible way in the future solid lighting applications.