Structural, Optical, and Electrical Properties of Tin-Doped CuS Nanoparticles for Photocatalytic Enhancement and Heterojunction Diode

Tin-doped copper sulfide nanoparticles were prepared by the co-precipitation method. The formation of the covellite phase was confirmed by x-ray diffraction (XRD) analysis. The optical band gap for pure CuS was found to be 1.72 eV and it decreased to 1.40 eV while increasing the doping percentage. The morphology and the elemental composition of the samples were analyzed by FESEM and EDX, respectively. The absorption of nanoparticles shows the plasmonic and band-edge absorption. Sn 5 at.% doping in CuS was found to be more catalytic than other samples. I-V measurements were carried out using the drop-casting method on n-type silicon, and the results indicate diode characteristics. For the heterojunction diode, the electrical parameters were calculated, and barrier height was determined to be in the range of 0.857-0.896 V. It was observed that the doping of Sn was affecting the barrier height, saturation current, and ideality factor. The mechanism of tuning the electronic and optical properties of Sn-doped CuS demonstrates a promising application as a heterojunction diode, and as a catalytic material, which have been discussed in detail.