Influence of annealing on p-type Cu₂ZnSnS₄ thin film by dip coating solution growth technique for the application of solar cell

Abstract

Thin films of Cu₂ZnSnS₄ have been deposited by solution growth dip coating method. Different Cu/Zn/Sn/S molar ratios were applied, which tells the properties of copper, Zinc, Tin, and Sulfide using X-ray diffraction, UV–vis, Energy dispersive X-ray spectroscopy, and scanning electron spectroscopy. The pure CZTS thin film showed the phase transformation from Kesterite (tetragonal) to Kesterite (orthorhombic) crystal structure. Optical measurement analysis reveals that layers have relatively high absorption coefficient in the visible spectrum with a band gap reduction of 1.51–1.49 eV with an increase in the annealing temperature from room temperature to 300 °C for 1 h in hot air furnace without any presence of an inert gas. Optical conductivity was observed to increase from 10¹² to 10¹³ (sec)⁻¹ and electrical conductivity was of the order of 10² (Ω cm)⁻¹.

Keywords:

• solar cell
• CZTS orthorhombic crystal
• Kesterite CZTS
• thin film
• chalcogenide
• optical conductivity
• globus structure
• band gap
• phase formation