ITO films for solar cells made by chemical solution deposition

The simplicity and low cost of indium tin oxide (ITO) thin films prepared by chemical solution deposition (CSD) through spin-coating has made this technique advantageous compared to other alternatives. By adjusting the precursor composition and temperature treatment procedure a transition to heterogeneous crystallization of CSD ITO films was promoted in this work. A columnar grain structure with preferred (111) orientation was observed. Transmission electron microscopy (TEM), electrical conductivity measurements, ellipsometry and atomic force microscopy (AFM) were used for an analysis of the ITO films properties. The surface passivation properties were investigated by means of the effective recombination lifetime as measured by the quasi-steady-state photoconductance (QssPC) technique. It is found that the CSD ITO films have a bit better passivation properties of silicon surface compared to magnetron sputtered ones. This result can be attributed to the “softer” conditions, which the CSD method provides. Application of CSD ITO films for the low-cost processing of heterojunction Si based solar cells are estimated and discussed.