Solution Processed p-Type Cu2ZnSnS4 Thin Films for Absorber Layer

Thin films of quaternary chalcogenide Cu2ZnSnS4 (CZTS) were prepared due to its abundance and non-toxic nature by chemical spray pyrolysis technique with 2-methoxyethanol as solvent for the precursor solution that avoids the insoluble base by-products of zinc and tin. The solution was clear without precipitates as the solvent has higher viscosity compared to DI water which resulted in the successful deposition of smoother films. The structural, morphological, optical and electrical properties of the films at different temperatures 280, 300, 350 and 400 A degrees C were investigated. The structural formation of kesterite Cu2ZnSnS4 was confirmed with a preferential (112) phase and with an intensed 334 cm(-1) Raman frequency mode.Uniform film growth and crack-free surface was obtained at a temperature of 350 A degrees C which was confirmed from morphological studies. The optical absorption showed a continuous absorption in the UV-Visible region and the obtained band gap for the films was in the range of 1.45-1.62 eV. The electrical study using Hall measurement proved the p-type conductivity of CZTS thin films which is pertinent for an absorber layer in thin film photovoltaic cell. A p-n junction was formed with TiO2 and CZTS materials and the light and dark current response was studied.