Fabrication of a Cu₂Sn1_-xGe_xS₃thin film by the sol-gel sulfurization method

Abstract

Cu 2 Sn 1-x Ge x S 3 (CTGS), which has characteristics suitable for the light absorption layer of single junction solar cells and is expected because an abundant and non-toxic element, was deposited by the sol-gel sulfurization method. The main peak of the sample sulfurized at 600 °C shifted by 0.44°to the higher angle side from Cu 2 SnS 3 (200) (CTS). From the peak shift angle, the chemical composition ratio of Ge/(Sn+Ge) was estimated to be 0.57. From SEM and EPMA results, Sn was evaporated from the film surface at high temperature during a sulfurization process. Therefore, the film surface became Ge-rich. From the results of Raman spectrum observation, CTGS near the substrate contained graphite. The band gap energy inferred from the (ahν) 2 -plots was lower than the reported band gap energy of CTGS. The lower band gap energy was considered to be due to the lower graphite-rich layer.

Silver sulfide thin film solar cells: materials, fabrication methods, devices, and challenges

“…The sulfuration method is characterized by its simplicity in processing, higher cost, and specific conditions required to obtain the desired product, such as low Gibbs free energy of reaction, temperature, inert gas atmosphere, and sulfuration agent concentration. [71][72][73] E. Barrera-Calva et al successfully prepared well-crystallized Ag 2 S thin films using a simple sulfuration method. The specific steps are as follows: firstly, a certain thickness of metallic Ag film is deposited on a glass substrate using a high-vacuum thermal evaporation apparatus.…”