Structural and Optical Characterization of Zinc Telluride Thin Films

Abstract

Group II-VI compounds have been investigated largely in last two decades due to their interesting optoelectronic properties. ZnTe, a member of this family, possesses a bandgap around 2.26eV. This material is now a day investigated in thin film form due to its potential towards various viable applications. In this paper, the authors report their investigations on the preparation of ZnTe thin films using vacuum evaporation technique and their structural and optical characterizations. The structural characterization, carried out using an X-ray diffraction (XRD) technique shows that ZnTe used in present case possesses a cubic structure. Using the same data, the micro strain and dislocation density were evaluated and found to be around 1.465×10-3lines-m2and 1.639×1015lines/m2respecctively. The optical characterization carried out in UV-VIS-NIR region reveals the fact that band gap of ZnTe is around 2.2eV in present case. In addition to this, it was observed that the value of bandgap decreases as the thickness of films increases. The direct transitions of the carries are involved in ZnTe. Using the data of UV-VIS-NIR spectroscopy, the transmission coefficient and extinction coefficient were also calculated for ZnTe thin films. Besides, the variation of extinction coefficient with wavelength has also been discussed here.

An overview on the role of ZnTe as an efficient interface in CdTe thin film solar cells: a review

“…Thin film solar cells are comprised of several thin film layers and a variety of strategies is available thus far to develop them, [82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] providing diverse properties. An overview of the physical and chemical routes is presented in Fig.…”

“…Thin film solar cells can be developed with better efficiency and stability by optimizing the thickness and properties of their different constituent layers, i.e., window, absorber, buffer and contact layers. As stated, a variety of deposition techniques has been employed thus far to grow the constituent layers, which are classified as follows: (a) physical and (b) chemical routes, where the resistive heating thermal evaporation, electron beam evaporation, molecular beam epitaxy, sputtering, and electrodeposition techniques have been used thus far for the fabrication of ZnTe thin films, [82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] providing diverse properties. An overview of the physical and chemical routes is presented in Fig.…”

Thickness Effect on Some Physical Properties of RF Sputtered ZnTe Thin Films for Potential Photovoltaic Applications

“…Due to characteristics obtained at the time of the deposition process such as: low resistivity, high transparency in the visible spectrum, etc. [ 1 , 2 , 3 , 4 ], thin layers of zinc telluride (ZnTe) are used in various modern technologies, which are implemented in various micro- and nano-structured devices, such as light emitting diodes, solar cells, photodetectors, etc. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

“…[ 1 , 2 , 3 , 4 ], thin layers of zinc telluride (ZnTe) are used in various modern technologies, which are implemented in various micro- and nano-structured devices, such as light emitting diodes, solar cells, photodetectors, etc. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Although it is a popular material, there are few publications and studies regarding its material engineering.…”

“…The ZnTe thin layer properties depend directly on the deposition method, deposition conditions, and the growth direction imposed by the substrate when the substrate is crystalline [ 5 , 6 , 7 , 8 , 23 ]. Some studies have established the ideal deposition conditions for various deposition methods, to obtain ZnTe layers with the necessary physical properties, a well-defined morphology, and crystal structure, but there is no systematic reproducible technology available for high performance ZnTe coating fabrications [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 24 , 25 ]. In this context, studies regarding correlation for growth conditions/parameters with ZnTe structuring and morphology, in correlation with their physical properties, are still very important.…”