Synthesis of enhanced (Sn$_{0.05}$Sb$_{0.15}$)$_2$(Te$_{0.02}$Se$_{0.18}$)$_3$ crystals for multi-sensing applications

Abstract

Crystals of (Sn$_{0.05}$Sb$_{0.15}$)$_2$(Te$_{0.02}$Se$_{0.18}$)$_3$ have been grown by the direct vapor transport technique. The challenge of intrinsic low electrical conductivity of antimony triselenide (Sb$_2$Se$_3$) was overcome by using tin (Sn) and tellurium (Te) as doping agents to synthesize (Sn$_{0.05}$Sb$_{0.15}$)$_2$(Te$_{0.02}$Se$_{0.18}$)$_3$ alloy. The chemical composition and surface topology analysis have been carried out using energy dispersive analysis of X-ray and scanning electron microscope, respectively. The structural properties of grown crystals were characterized by powder X-ray diffraction (XRD) technique and have been compared with data of Sb$_2$Se$_3$ crystal. The XRD analysis revealed the orthorhombic structure of grown crystals. The spot pattern in the selected area electron diffraction image indicates good crystalline nature of grown crystals. Different phonon modes were analyzed using Raman spectroscopy. The optical properties have been characterized using diffuse reflectance spectroscopy. The photo-detection and trap depth parameters were examined for different wavelengths and illumination intensities. Also, non-oxide semiconductor-based gas sensor and human breathing sensor have been studied. The effect of doping was clearly seen in the enhancement of sensing properties of the grown crystals.