Study on the optical absorption and green emission of ZnO phosphors by varying Al doping contents

The blue band optical absorption and green luminescence of ZnO phosphors doping with aluminum are systematic studied. The Al content is varied from 0.01 at.% to 1 at.%. SEM images illustrated that Al doping can effectively suppress the ZnO grain growth. XRD results clearly manifest that the Al solubility limit in ZnO is around 0.1 at.%. It is also found that the E1 (LO) vibration mode in the Raman spectra exhibits a good correlation with the blue band optical absorption and green photoluminescence. The results revealed that both VO0 and VO+ can give rise to the E1 (LO) vibration mode. We conclude that the VO and Oi defects are the dominant reason of the green photoluminescence in ZnO phosphors, in oxygen-deficient and oxygen-rich conditions, respectively.

► E1 (LO) mode has a good relation with the 410 nm absorption and green emission.
► Results indicated that both VO0 and VO+ give rise to the E1 (LO) vibration mode.
► VO and Oi defects contribute to the green photoluminescence in ZnO.
► Each will be dominated in O-deficient and O-rich conditions, respectively.