Solution enhancement for the liable preparation of Cu2ZnSnS4 thin films

Abstract

The role of precursor solution is vital in the chemical spray pyrolysis deposition of Cu2ZnSnS4 (CZTS) thin films. The solubility of metal precursors along with organosulfur compound in repetitive conditions is demanding for the preparation of CZTS precursor solution. The regular aqueous solution and a viscous 2-metho solvent were taken for the preparation of CZTS thin films using spray pyrolysis technique. The aqueous and 2-metho films were deposited and characterized to reveal their structural, morphological, optical and electrical properties. The structural studies confirmed the formation of Cu2ZnSnS4 tetragonal phase. The film growth on the surface and the roughness values were analyzed from FESEM and AFM analyses which showed a glut roughness for aqueous film. The optical absorbance showed maximum response in the UV–Visible region with a cut off in the near IR region which is a suitable parameter for absorber layer in thin films solar cells. The photoluminescence spectrum gave an emission peak in the near IR region. The electrical measurement specified a carrier concentration of 1.36 × 1015 cm−3 for 2-metho film which was higher than the aqueous ones of 1.25 × 1015 cm−3. The p-type semiconducting behavior of the material was confirmed from the Hall measurement and the impedance analysis was studied. The V–I measurement gave a linear response and the resistance values of the deposited thin films were calculated.