Nebulizer spray assisted chemical vapour deposited (NACVD) tin disulfide (SnS2) thin films for solar cell window layer applications

Abstract

The prospective nontoxic Tin disulfide (SnS2) thin films have been fabricated through nebulizer spray assisted chemical vapour deposition (NACVD) method by varying carrier gas pressure as 0.05, 0.1 and 0.15 Pa at 325 degrees C temperature on soda lime glass substrates. Exceedingly single crystalline phase SnS2 film coated uniformly on the substrate was observed from structural and morphological analysis. Optical studies of the fabricated films reveal a decrement ofband gap from 2.85 eV to 2.65 eV as pressure of carrier gas increased from 0.05 Pa to 0.15 Pa. The emitted photoluminescent (PL) intensity was strong at about 561 nm which is related to the near band edge (NBE) emission of SnS2. Hall analysis showed the value of conductivity and carrier concentration of SnS2 in the range of 6.84 x 10(-5) to 1.34 x 10(-3) Omega(-1) cm(-1) and 2.47 x 10(13) to 7.18 x 10(13) cm(-3) , respectively. This study confirms that a superior device quality SnS2 thin film can be fabricated and can be used as a nontoxic window layer through low cost NACVD method by optimizing the carrier gas flow rate and other factors such as temperature of the substrate and precursor concentration. A good interface between the window and absorber layers minimizes the recombination and aids to increase the efficiency of a photovoltaic cell structure.