Sol-gel based Cd(II)-doped In2O3 transparent conducting thin film on glass

Precursor sols of cadmium-doped indium oxide system with different dopant concentrations (In:Cd = 99:1-90:10) have been prepared from the corresponding metal salt solutions in alcoholic medium. Films are deposited on glass by sol-gel dipping process. The XRD study of the air cured films reveals formation of both bixbyite phase of indium oxide and cubic phase of cadmium oxide. From the FESEM analysis of film surface, line defects are identified for low dopant concentration. Particle size of the film materials processed under differential partial pressures of oxygen gas is determined. The TEM image of the lowest dopant concentration (In:Cd = 99:1) sample exhibits cluster dimension similar to 24 nm. HRTEM identifies the formation of screw dislocations. Sheet resistance was recorded as 800-1000 ka/ for the lowest dopant concentration (In:Cd = 99:1). Evidence for highly transparent feebly conducting films is produced. On Cd doping, formation of interstitial solid solution instead of substitutional solid solution has been predicted. Band gap of the doped system has been evaluated from their absorption spectra. Photoluminescence study explores major oxide defects in the film material. Magnified view of HRTEM image of ICO-1 particles cured at 500 A degrees C for 1 h. in air showing distorted lattice lines, a screw dislocation (marked arrow head).