Growth and characterization of some transparent conducting oxide thin films

Abstract

In the present work we have prepared thin films of three TCO materials, viz. indium oxide (IO), indium silver oxide (IAO) and indium tin oxide (ITO) by varying the required coating parameters. The films were coated on soda lime glass substrates. The coated films were characterized structurally by x-ray diffraction measurements. Thickness measurements were carried out by both optical and ellipsometric methods. Optical, electrical and magnetic characterizations were carried out for the samples using the standard methods as per the requirement. newline The electrical and optical properties of IO films have been studied for various substrate temperatures. The resistivity of thin films were in the order of 1.0 x 10-4 ohm-cm and an optical transparency of 85%. It was found that the EMI shielding efficiency (SE) of IO films (of 100nm thickness) was very much comparable to that of the silver coated metal sheet in the measured frequency range 1MHz till 800 MHz. The conducting carrier density and AC magnetic susceptibility studies were made for the as-coated film. The analysis of our results clearly shows that the required properties of IO films were well suited for the suppression of EMI. newline Transparent conducting oxides are, generally, of n-type. In the present study we have obtained thin films of In2O3 + Ag2O, indium silver oxide (IAO), prepared on soda lime glass substrate by electron beam evaporation technique for various substrate temperatures (180 250and#61616;C) and chamber pressure maintained at 2.5 x10-4 torr with oxygen as the reactive gas. The electron beam current was varied between 30-100 mA keeping the voltage at 3.8 kV. Two combinations of tin concentrations were studied (20% and 40%). It was found that all the films grown at higher rate of evaporation were polycrystalline. The type of conductivity (p-type or n-type) in these films is observed to be dependent on the evaporation rate.