Electrical and optical studies on amorphous Se-Te alloys
Electrical and optical studies on amorphous Se-Te alloys
复制标题
非晶 Se-Te 合金的电学和光学研究
DOI：
10.1088/0022-3727/25/12/017
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
A. Bhatnagar
中科院分区：
文献类型：
--
作者：
K. Reddy;A. Bhatnagar
制备了Se_(1-x)Tex半导体玻璃，并对其进行了光学、电学和X射线表征。结果发现，只有用常规的淬火技术才能制备出x约为0.30的均匀的Se_(1-x)Tex玻璃，而没有任何可检测到的结晶度。由于Se_(1-x)Tex玻璃在可见光区的高吸光度，首次用光声吸收光谱研究了它们的光学能隙随x的变化，发现非晶态Se的光学能隙Eg比c-Se的高0.12 eV。观察到，Te在a-Se中的初始小取代量迅速减小，Eg。对于x>；0.10，Eg的变化变得较小，并且与x成线性关系。电导率的温度依赖性表明，这些玻璃中的电子传导是通过扩展态进行的。活化能和电导前因子均随x减小，并在x约为0.1时出现突变。用电荷缺陷模型和能带拖尾理论解释了这些结果。
Se1-xTex semiconducting glasses have been prepared and characterized by optical, electrical and X-ray measurements. It is found that homogeneous Se1-xTex glasses can only be prepared, without any trace of detectable crystallinity, up to x approximately=0.30 by the usual conventional quenching technique. Due to the high absorbance of Se1-xTex glasses in the visible region, photoacoustic absorption spectroscopy has been used for the first time to study their optical energy gap variation as a function of x. The optical energy gap Eg of amorphous Se is found to be about 0.12 eV higher than that of c-Se. It is observed that initial small substitution of Te into a-Se rapidly decreases Eg. For x>0.10, the variation in Eg becomes smaller and linear with x. Temperature dependence of the conductivity suggests that the electronic conduction in these glasses takes place via extended states. The activation energy and conductivity prefactor both decrease with x and show sudden changes at x approximately=0.1. An attempt is made to explain these results based on the charge defect model and the tailing of energy bands in the gap region.