Simultaneous synthesis of various Sb2S3 nanostructures by vapor transport technique

In this study, we report the preparation of different Sb2S3 morphologies in the same experimental setup. We utilized the method of vapor phase transport with direct evaporation of high purity Sb2S3 powder on quartz and Si (100) substrates. The deposited Sb2S3 nanostructures showed different morphologies and crystallinities without using metal catalyst seed layers. The successfully formed Sb2S3 morphologies were nanowires, nanorods, nanodendrites and nanoparticles, as verified by the scanning electron microscopy and transmission electron microscopy analysis. We found that the physical characteristics of the final product are a function of the differential temperature inside the furnace tube. The X-ray diffraction analysis confirmed the formation of the orthorhombic pure phase of crystalline stibnite-Sb2S3. The energy-dispersive X-ray spectroscopy spectra validated the high purity of the synthesized products. Moreover, the relation of the morphology and the optical and electrical properties of Sb2S3 thin films have been studied by various techniques. The optical analysis by UV-vis-near-infrared (NIR) spectroscopy shows that the optical band gaps of the different synthesized films range from 1.64 to 1.92 eV. The refractive indices (n) of Sb2S3 thin films were found to be morphology dependent. The film with nanoparticles morphology has the highest n value of 2.1 and the film with nanowires morphology has the lowest n value of 1.97. In all prepared samples photoluminescence (PL) spectra exhibit a distinct emission peak at 615 nm (similar to 2.02 eV) in terms of intensity and FWHM. The dc-electrical conductivity of various Sb2S3 nanostructures is thermally activated according to Arrhenius law with two types of conduction mechanisms. The conduction in the high temperature and lower temperature zones is due to the hopping conduction via localized states and the thermionic emission respectively. The study provides a framework for future research in semiconductor nanomaterials with controllable morphologies for applications of optoelectronics.