<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:HiddenHorzOCR; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Optical and <span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">transport properties <span style="font-size:14.0pt; line-height:115%;font-family:"Times New Roman";mso-fareast-font-family:HiddenHorzOCR; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">of CdS_1-x Te_x <span style="font-size:14.0pt;line-height:115%;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";color:black; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">alloyed thin <span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:HiddenHorzOCR;color:black; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">films</span></span></span></span></span>

Abstract

A good deal of information regarding synthesis optical and electrical transport properties of the chemically grown CdS_1-x Te_x thin film structures is presented. Growth of these films depend upon various preparative parameters and deposition conditions such as temperature, <i>p</i>H, time, concentration, speed of the mechanical churning etc and the reaction kinetics suggests that the films grow in two different phases; an initial quasi -linear and second a saturation. The as-deposited films are crystalline over the whole range of the composition parameter and both CdS and CdTe are deposited as a mixture of the hexagonal wurtzite and cubic zinc blende structures (hexagonal being dominant). The solid solution is observed for hexagonal phase in the 0≤<i>x</i> ≤0.1 and 0.9≤ <i>x</i>≤ 1 regions. In the middle range (0.1<<i> x</i> < 0.9), separate phases of both CdS and CdTe have been detected. Optical absorption studies revealed a high absorption coefficient (10⁴-10⁵ cm^-1) with a direct type of transition. The estimated bandgap decreased almost linearly with the composition parameter, <i>x. </i>The room temperature

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">electrical conductivity is found to be increased initially with the composition parameter (0≤<i>x</i> ≤0.1) decreased for a further increased in<i> x</i> (0.1 < <i>x </i>< 0.8) and again increased for higher Te content in CdS. The material exhibits both grain boundary scattering limited and a variable range hopping conduction mechanisms. The thermoelectric power is negative showing n-type behaviour of the samples. Both carrier concentration (<i>n</i>)<i> </i>and mobility (μ) were computed and found to be sensitive functions of temperature.</span>