Solvothermal Synthesis, Structural and Optical Properties of Phase-Pure Cu_3BiS_3 Nano-Powders Exhibiting Near-IR Photodetection

摘要

The Cu_3BiS_3 with a direct band gap of 1.4 eV, crystallizing in orthorhombic phase, devoid of any rare earth metals like indium was synthesized using a facile solvothermal route at 170 ℃ for 8 hrs. The structure and composition of the obtained nano-powders were confirmed by X-ray powder diffraction(XRD), field-emission scanning electron microscopy(FESEM), transmission electronic microscopy(TEM)and X-ray photoelectron spectroscopy(XPS). The optical properties of the Cu_3BiS_3 nanorods were investigated by Raman and UV-Visible spectroscopy. Out of 36 Raman active modes, 16 modes were pronounced remaining silent. The current-voltage measurements were performed over the Cu_3BiS_3 film, on sandwich and in-plane geometries both in dark and light conditions. Measurements showed that in sandwich geometry, the I-V curves followed the SCLC mechanism at a higher bias, and thermionic emission in the in-plane geometry at a lower bias. In-plane IR photoresponse was higher compared to sandwich geometry.