The photoluminescence of ZnSe bulk single crystals excited by femtosecond pulse
Li Huan-Yong(李焕勇)a)b)†, Jie Wan-Qi (介万奇)b), Zhang Shi-An(张诗按)c), Sun Zhen-Rong(孙真荣)c), and Xu Ke-Wei(徐可为)a)
a State Key Laboratory for Mechanical Behavior of Materials, Xi`an Jiaotong University, Xi'an 710049, China; b College of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China; c Key Laboratory for Optics and Magnetic Resonance Spectroscopy, Department of Physics, East China Normal University. Shanghai 200062, China
Abstract This paper reports on the photoluminescence spectra of ZnSe single crystal with trace chlorine excited by the femtosecond laser pulse. Three emission bands, including second-harmonic-generation, two-photon-excited peak and a broad band at 500--700nm, were detected. The thermal strain induced by femtosecond pulse strongly influences the photoluminescence of ZnSe crystal. The corresponding strain $\varepsilon$ in ZnSe crystal is estimated to be about $8.8\times10^{-3}$ at room temperature. The zinc-vacancy, as the main point defect induced by femtosecond pulse, is successfully used to interpret the broad emission at 500--700nm. The research shows that self-activated luminescence possesses the recombination mechanism of donor--vacancy pair, and it is also influenced by a few selenium defects and the temperature. The rapid decrease in photoluminescence intensity of two-photon-excited fluorescence and second-harmonic generation emission at lower temperature is attributed to the fact that more point defects result in the thermal activation of the two-photo-absorption energy converting to the stronger recombination emission of chlorine--zinc vacancy in 500--700nm. The experimental results indicate that the femtosecond exciting photoluminescence shows a completely different emission mechanism to that of He--Cd exciting luminescence in ZnSe single crystal. The femtosecond laser exhibits a higher sensitive to the impurity in crystal materials, which can be recommended as an efficient way to estimate the trace impurity in high quality crystals.
Received: 15 June 2005
Revised: 05 June 2006
Accepted manuscript online:
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos 50502028 and 50336040) and the China Postdoctoral Science Foundation (Grant No 2004036139).
Cite this article:
Li Huan-Yong(李焕勇), Jie Wan-Qi (介万奇), Zhang Shi-An(张诗按), Sun Zhen-Rong(孙真荣), and Xu Ke-Wei(徐可为) The photoluminescence of ZnSe bulk single crystals excited by femtosecond pulse 2006 Chinese Physics 15 2407
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