Full Paper Structural, optical and electrical properties of indium doped cadmium oxide thin films Nadir F.Habubi 1 *, Ramiz A.Al-Anssari 2 , Jinan Ali Abd 2 1 Al-Mustansiriyah University, College of Education, Physics Department, (IRAQ) 2 Baghdad University, College of Science for Women, Baghdad, (IRAQ) E-mail : nadirfadhil@yahoo.com Thin film; Structural properties; CdO; CdO:In; Optical properties; Hall measurements. KEYWORDS ABSTRACT Conducting and transparent indium doped CdO thin films were prepared by spray pyrolysis on a glass substrate with various concentration of indium (28 wt%) in the spray solution. The optical and structural proper- ties of indium doped and undoped CdO films were studied utilizing optical transmission, X-ray diffraction and atomic force microscope. X-ray analy- sis shows that the doped and undoped CdO films are preferentially orien- tated along (111) crystallographic directions. Increase of indium doping concentration increases the films packing density and reorient the crys- tallites along (1 1 1) plane. There is a decrease in the optical transmissions for all films with the decrease in wavelength. The light transmission of CdO films increases as In doping level increases. The optical band gap value of CdO was equal to 2.55 eV and it was increase with doping con- centration and reaches a maximum value of 2.65 eV at 4 wt% indium dop- ing. Low resistivity achieved in the present study was found to be 0.910 - ‡(.cm) at 4wt% In doping.  2013 Trade Science Inc. - INDIA An Indian Journal Trade Science Inc. Volume 7 Issue 5 Nano Science and Nano Technology Nano Science and Nano Technology NSNTAIJ, 7(5), 2013 [172-178] ISSN : 0974 - 7494 INTRODUCTION Transparent conducting oxides (TCOs) are mate- rials that possess both high electrical conductivity, high optical transparency (> 80%) in the visible light region of the electromagnetic spectrum. These are remarkable materials in that the above properties are generally mu- tually exclusive and are hard to find in the same mate- rial. Cadmium oxide is a n-type semiconductor with non- stoichiometric composition due to the presence of ei- ther interstitial cadmium or oxygen vacancies, which act as doubly charged donors [1] , with nearly metallic con- ductivity. One of the ways of tailoring the band gap is by synthesis a new semiconductor phases with large/ small band gap semiconductors. The band gap of cad- mium oxide can be thus tuned over a wide range from 1.1 eV to 3.3 eV by alloying with suitable materials. These alloyed semiconductors have a number of inter- esting applications in electrochemical or photoelectro- chemical devices, phototransistors, photodiodes, gas sensors, etc. [2-4] . CdO thin films have been prepared by various physi- cal and chemical deposition techniques such as pulsed laser deposition [5,6] , spray pyrolysis [7-9] , sol gel [10,11] , DC magnetron sputtering [12-14] , RF sputtering [15] , chemical bath deposition [16] and thermal evaporation [17-19] .