Exploring the physical and electrical properties of Li and Na Co-doped SnS material

This study explores the effect of Li (1 at%, fixed) and Na (1 at%, 2 at%, and 3 at%) co-doping on the physical, optical, and electrical performance of SnS material synthesized via a hydrothermal approach. As a chalcogenide compound, SnS is an earth-abundant, cost-effective material with lower toxicity compared to similar compounds such as GeS, PbS, GeTe, and PbTe. Notably, tin sulfide (SnS) holds great potential for energy storage applications due to its unique layered structure and anharmonic bonding. The phase purity of all the samples was confirmed through powder XRD pattern, which aligned well with the standard JCPDF file (PDF#075–2115). The surface morphology was assessed using field emission scanning electron microscopy (FESEM), while energy dispersive X-ray (EDX) analysis provided insights into the chemical composition and elemental distribution of the samples. UV–Vis absorption spectroscopy showed a reduction in the band gap value of Li and Na co-doped SnS compared to the bare SnS sample, reaching a minimum of 1.30 eV for the Li (1 at%, fixed) and Na (3 at%) co-doped SnS sample, as determined from the Tauc plot. The chemical bonds and functional groups present in the samples were explored via FTIR spectroscopy, and the thermal stability was evaluated through thermogravimetric analysis (TGA).

To assess the electrical characteristics, Hall Effect measurements were performed at room temperature (305 K), confirming p-type semiconducting behavior of all the samples. Among the tested compositions, the Li (1 at%, fixed) and Na (3 at%) co-doped SnS sample exhibited the highest carrier concentration (n = 6.57 × 10¹⁸ cm⁻³) and superior electrical conductivity (0.22 S/cm), outperforming both bare and other co-doped samples.