Photoluminescence behaviors in ZnGa_2O_4 thin film phosphors deposited by a pulsed laser ablation

摘要

ZnGa_2O_4 thin film phosphors have been deposited using a pulsed laser deposition technique on Si (1 0 0) and Al_2O_3 (0 0 0 1) substrates at a substrate temperature of 550 ℃ with various oxygen pressures 100, 200 and 300 mTorr, and various substrate temperatures of 450, 550 and 650℃ with a fixed oxygen pressure of 100 mTorr. The films grown under different deposition conditions have been characterized using microstructural and luminescent measurements. Under the different substrate temperatures, ZnGa_2O_4 thin films show the different crystallinity and luminescent intensity. The crystallinity and photoluminescence (PL) of the ZnGa_2O_4 films are highly dependent on the deposition conditions, in particular, oxygen pressure, substrate temperature, a kind of substrates. The luminescent spectra show a broad band extending from 350 to 600 nm peaking at 460 nm. The PL brightness data obtained from the ZnGa_2O_4 films grown under optimized conditions have indicated that the sapphire is one of the most promised substrates for the growth of high quality ZnGa_2O_4 thin film phosphor.