Zhang Sen, Chen Yimin, Wang Rongping, Shen Xiang, Dai Shixun
Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo, Zhejiang, 315211, China.
Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, 315211, China.
Sci Rep. 2017 Nov 6;7(1):14585. doi: 10.1038/s41598-017-14796-w.
We presented the unusual result of photobleaching (PB) in Ge-deficient GeSe thin films with continuous irradiation with 560 nm laser for 12000 s, which is contradicted with the previous reports that the PB only occurs in GeSe films with x > 30. Observation of the dynamics variations of the photo-induced effects indicated that, photodarkening (PD) appears almost instantaneously upon light irradiation, saturates faster in a shorter time scale, and then photobleaching (PB) becomes dominant. Moreover, both PD and PB process accelerates with increasing irradiation power density. Raman spectra provided the evidence on the change of the photostructure of the samples, e.g. the structural transformation from Ge(Se) edge-sharing (ES) to corner-sharing (CS) tetrahedral and homopolar Ge-Ge and Se-Se bonds to heteropolar Ge-Se bonds.
我们展示了在缺锗的GeSe薄膜中，用560纳米激光连续照射12000秒时发生的异常光漂白（PB）结果，这与之前报道的PB仅发生在x>30的GeSe薄膜中的情况相矛盾。对光致效应动力学变化的观察表明，光暗化（PD）在光照后几乎立即出现，在较短时间尺度内更快达到饱和，然后光漂白（PB）占主导。此外，PD和PB过程都随着辐照功率密度的增加而加速。拉曼光谱提供了样品光结构变化的证据，例如从Ge(Se)边共享（ES）到角共享（CS）四面体的结构转变，以及从同极Ge-Ge和Se-Se键到异极Ge-Se键的转变。
