Chalcogenide Letters Vol. 7, No. 1, January 2010, p. 21 - 29 STRUCTURAL, ELEMENTAL COMPOSITIONS AND OPTICAL PROPERTIES OF ZnTe:V THIN FILMS M. S. HOSSAIN a* , R. ISLAM b , K. A. KHAN b a Department of Physics, Rajshahi University of Engineering & Technology, Rajshahi-6204, Bangladesh b Department of Applied Physics and Electronic Engineering, University of Rajshahi, Rajshahi-6205, Bangladesh Vanadium doped zinc telluride (ZnTe:V) thin films of various thicknesses for a particular composition of 2.5wt% V were deposited onto glass substrates by e-beam evaporation technique in vacuum at a pressure of 8×10 -4 Pa. The deposition rate of the ZnTe:V films was maintained at 2.05 nms -1 . The optical properties of ZnTe:V thin films for different film thicknesses have been studied in detail. Structural study of the films was performed by x-ray diffraction technique and it was found that the films are mixed crystalline in nature. Surface morphological study was done by using SEM technique. EDAX method was also used to determine the elemental composition in deposited thin films. The optical properties of as-deposited and annealed ZnTe:V films for different thicknesses were studied in the wavelength range 300 < λ < 2500 nm, respectively. For both types of samples, the values of the Urbach tail energy, optical band gap, refractive index, extinction coefficient and real part of dielectric constants were evaluated for different film thicknesses, respectively. Evaluation of these parameters may help in view of their technological applications in selective surface as well as in optoelectronic devices. (Received December 22, 2009; accepted January 14, 2010) Keywords: ZnTe:V thin film, E-beam evaporation technique, Surface morphology, Urbach tail energy, Optical band gap, Refractive index 1. Introduction ZnTe is a low cost semiconducting material of the II-VI family. This crystal is usually a cubic, zincblende type in structure with lattice constant a o = 6.1034 Å. Like most of the ZnTe crystals is normally a semiconductor. In thin film, it is more insulating than the bulk. Usually, it is a material of high absorption coefficient [1] and shows a p-type [2, 3] in nature. ZnTe has direct [1, 4] transition of wide band gap [1] of 1.7 to 2.4 eV at room temperature. ZnTe has recently been focused of great interest due its low cost, wide band gap and high absorption co-efficient for application to photovoltaic [5] and photoelectrochemical cells [6-9]. It is a promising compound for development of various solid state devices including the blue light emitting diodes [10, 11], laser diodes [12], solar cells [10-12], microwave devices [13] and various optoelectronic devices [14-16]. Literature reports [17, 18] indicate that the ZnTe exhibits improved photorefractive response when it is doped with vanadium. Vanadium is believed to be a suitable impurity in ZnTe and it has attractive use in a variety of applications including optical power limiting, optical computing and optical communication [18]. Since optical response is of great importance for many device applications, many efforts have been made to obtain optical response. Although there have been a number of investigations on the ZnTe films by a number of researchers, no systematic study appears to have been done on the structural and optical properties of ZnTe thin films in particular * Corresponding author: sazzad_phy@yahoo.com