Sputtered ITO for application in thin-film silicon solar cells: Relationship between structural and electrical properties

Indium tin oxide (ITO) thin films for application in thin-film silicon solar cells with superior electrical and optical properties (resistivity ranging from 1.4 to 8.4 x 10(-4) Omega cm; transparency of >80%) have been investigated. ITO layers were deposited by radio-frequency (RF) magnetron sputtering process at different argon gas pressures and substrate temperatures ranging from room temperature to 280 degrees C. The main goal was to identify the relationship between structural and electrical properties. Generally, ITO layers were rather smooth with granular topography; electro-optically superior layers exhibited substantially different surface morphology of large, well-organized domain formations. Hall mobility of remarkably high value of 49 cm(2)/V s (resistivity of 2.6 x 10(-4) Omega cm) was achieved for the ITO layers, which were deposited at surprisingly low temperature of 125 degrees C. ITO process has been successfully applied, even at room temperature, to fabricate front contacts for microcrystalline silicon solar cells, exhibiting excellent performance on both rigid and flexible substrates. (C) 2012 Elsevier B. V. All rights reserved.