Study of optoelectronics properties of indium tin oxide films fabricated by sputtering in oxygen atmosphere

Indium tin oxide (ITO) thin films were deposited by magnetron sputtering with different oxygen flows rates (%O₂ = 1 % to 0 %). The films were deposited by RF discharge in argon/oxygen atmosphere with a RF power W = 150 W at substrate temperature T = 175° C and pressure P = 6 mTorrs. Photoelectric parameters of fabricated ITO films were characterized by four-point probe method and transmittance measurements. It was found that reducing oxygen concentration the sheet resistance decreases. For samples fabricated in oxygen atmosphere the transmittance reached values above 90 %. However, the sample with post-deposition thermal treatment at T = 300 °C in oxygen atmosphere shows the best transmittance (95 %) and lowest value of sheet resistance (R_s= 27 ohms-square). Finally, the transparent conducting oxides were applied in hybrid organic-inorganic photovoltaic structures. The best power conversion efficiency in AM-1 sunlight η = 2.13 % was obtained for a structure with ITO fabricated at oxygen concentration %O₂ = 0.25 % in comparison with an efficiency η = 1.87 % obtained for a structure fabricated with commercial ITO.