Luminescent properties of ZnO structures grown with a vapour transport method

ZnO structures were synthesised on the sapphire (112?0) substrate by a vapour transport method in a gas flowing furnace. The influence of the oxygen content in the gas mixture on the morphology and luminescent properties of ZnO structures grown on a strip-like substrate was investigated, with all other growth parameters being kept nominally identical. Integrated electron microscopy and cathodoluminescence analysis shows gradual variations of structural and optical emission properties for ZnO structures grown on the long substrate. Defect-related green luminescence of ZnO is found to be highly dependent on the oxygen vapour in the growth region of the furnace. Our findings demonstrate that the green luminescence is associated with oxygen deficiency in ZnO.