Synthesis of π-SnS thin films through chemical bath deposition: effects of pH, deposition time, and annealing temperature

In this work, details of deposition and characterization of pi-SnS thin films with uniform and compact morphology deposited through chemical bath deposition are reported. Non-toxic tartaric acid is used as complexing agent. The effect of pH, deposition time, and annealing temperature on morphological, structural, chemical, optical, and electrical properties is investigated. The results show an increase in particle size with pH (5-8) and deposition time (2-6 h) in the as-deposited films, having values of 72-162 and 127-170 nm, respectively. Similarly, thickness increases with pH and deposition time in the range of 117-215 and 100-200 nm. The formation of pi-SnS is demonstrated by XRD and TEM analyses (lattice parameter a similar to 11.556 angstrom). Besides, Raman, FTIR, and XPS spectroscopy confirm the presence of some additional phases (SnO2) and impurities (CO- and COH). Optical measurements show that films have absorption coefficient higher than 10(4) cm(-1), while band-gap values are in the range of 1.72-2.01 and 1.53-2.00 eV for the as-deposited and annealed films. Electrical studies exhibit an increase in the dark and photoconductivity with pH and deposition time. Finally, the influence of CO-, COH, and SnO2 on solar cells' performance is discussed.