Photovoltaic effect of chemically deposited Cu2S/CSi heterojunctions

Abstract

Cu₂S/Si heterojunctions have been fabricated by chemically depositing Cu₂S thin films on n-type CSi substrates. Films grown on glass slides side by side had a thickness of 0.5 microns, resistivity of 2 × 10⁻¹ ohm cm and optical band gap of 1.9 eV. Ohmic back contact was made by electroless technique. The front grid was a spring-loaded metal mesh. Junction characteristics were measured on as-grown and air-annealed samples in dark and under illumination of 80 mW/cm². Annealing at 200°C showed substantial improvement on the junction characteristics. Typical values obtained on annealing are J_sc 110 μA/cm², V_oc 120 mV and F.F. = 0.36. Suggestions for further improvement are also mentioned.