An experimental and theoretical study on soft chemically grown CuS thin film for photosensor application

作者：Huse Nanasaheb P; Dive Avinash S; Gattu Ketan P; Sharma Ramphal^*

来源：Materials Science in Semiconductor Processing, 2017, 67: 62-68.

DOI：10.1016/j.mssp.2017.05.010

• CuS thin film
• Covellite structure
• Response time
• Photosensor
• DFT

Herein we report, the photosensitivity of in-situ chemical bath deposition (CBD) grown CuS thin film for the first time, also comparatively very short deposition time of 40 min and much lower bath temperature i.e. 45 degrees C are reported. The structural, surface topographical, optical, electronic and electrical properties of as-grown CuS thin film have been investigated. The XRD analysis revealed the formation of Orthorhombic (Covellite) structure with preferential growth along [113] direction having similar to 14 nm average crystallite size. Raman spectrum indicating a sharp peak at 474 cm(-1) confirms the formation of CuS covellite structure. Polycrystalline nature of the film has been confirmed from the concentric ring pattern obtained from TEM-SAED and AFM revealed the rough surface topography with RMS roughness of similar to 27 nm. The'bond lengths of Cu(1)-S(1) and S(1)-S(1) were obtained from the DFT calculations based on GGA approximation, suggest S-S bond is much stronger as compared to Cu-S bond; these results are in good agreement with the Raman result. The film shows higher absorbance in the visible region with a band gap of 2.2 eV. The electrical properties show a drastic increase in current after light illumination of 50 W which increases with increasing light intensity and tends to attain a saturation state around 200 W. The highest photosensitivity of similar to 66% has been calculated for 200 W with fast response time of similar to 34 s and a complete recovery. These results represent CuS thin films promising candidature for photosensor application.

• 出版日期2017-8-15