Fabrication of Cu2SnS3 thin films by dual-source fine channel mist CVD

Cu2SnS3 (CTS) thin films were prepared by a dual-source mist chemical vapor deposistion (CVD) method. Cu-Sn and S mist sources were prepared separately, without a vacuum apparatus or sulfurizing process to reduce cost and to prevent exfoliation of the deposited CTS thin film. The hot plate temperature was varied in the range 350-400 degrees C, and CTS thin films with a suitable morphology for solar cells were produced at 370 degrees C. However, the composition ratio varied significantly upstream and downstream of the mist flow. Moreover, the S/metal ratio for all obtained films was too low, as a result of a temperature drop due to the low-temperature mist flow. Therefore, the effect of reducing the lift gas flow rate for the Cu-Sn mist source on the CTS films was investigated to prevent this temperature drop. Samples fabricated with a reduced lift gas flow rate exhibited showed X-ray diffraction peaks attributed to the (200), ((1) over bar 31), ((1) over bar 33), and ((3) over bar 33) planes of monoclinic CTS, as well as monoclinic CTS Raman peaks. In addition, the estimated bandgap energy for the CTS thin films was 0.93-0.96 eV, which corresponds to that reported for monoclinic CTS. This indicates that the fabricated samples were monoclinic CTS deposited by dual-source fine channel mist CVD without the need for a sulfurization process.

Automated summary

In this study, Cu2SnS3 (CTS) thin films were prepared using a dual-source fine channel mist CVD method. By adjusting the hot plate temperature and reducing the lift gas flow rate, CTS thin films with suitable morphology for solar cells were obtained without the need for a vacuum apparatus or a sulfurization process.