Mechanism of blue shift of optical band gap in aluminum-doped ZnO thin films with blend bond
In this paper, aluminum–doped nano-crystalline zinc oxide (ZnO:Al or AZO) thin films were deposited on fused quartz substrate by pulsed laser ablation at various temperatures. The physical phase and surface morphology were characterized by using X-ray diffraction (XRD) and atomic force microscope (AFM), respectively. The variation of the optical band gap (Eg opt) of the films with the temperature was measured through transmittance in UV-VIS wavelength. The results showed that there was a blue shift of Eg opt from 3.44 eV to 3.62 eV as the growing temperature decreased from 500℃ to 200℃. The value of Eg opt immediately recurred from 3.30 to 3.35 eV after a thermal annealing of the samples at 700℃, inclining to a normal value of bulk zinc oxide. The analyses of XRD and AFM testified that the presence of amorphous phase in the AZO films was the main reason for the blue shift of the optical band gap Eg opt.
ZnO films PLD optical band gap blue shift
L.Shen C.Shen J.Yang F.Xu Z. Q.Ma
SHU-SolarE R&D Lab, Department of Physics, Shanghai University,Shanghai 200444, P.R. China SHU-SolarE R&D Lab, Department of Physics, Shanghai University, Shanghai 200444, P.R. China
国际会议
11th IUMRS International Conference in Asia(第十一届国际材联亚洲材料大会 IUMRS-ICA 2010)
青岛
英文
98-104
2010-09-25（万方平台首次上网日期，不代表论文的发表时间）