Growth and characterizations of indium doped tin diselenide (InxSn1−x)Se2 crystals

Nowadays, materials with narrow bandgap of transition metal dichalcogenide layered structures have attracted towards the research due to their substantial and tunable optoelectronic properties. Among the IV-VI compound semiconductor, (In${}_x$Sn${}_{1-x}$)Se${}_2$ is potential candidate with higher carrier mobility, sustainability and getting higher carrier concentration with doping. The (In${}_x$Sn${}_{1-x}$)Se${}_2$ crystal is layered type crystal grown by direct vapor transport mode within vacuum closed quartz ampoule. The chemical composition of (In${}_x$Sn${}_{1-x}$)Se${}_2$ grown crystals have been confirmed by Energy Dispersive X-ray analysis. Also it showed that as grown (In${}_x$Sn${}_{1-x}$)Se${}_2$ crystals to be near the stochiometric rich with Se. The structure analysis by X-ray diffraction of as grown (In${}_x$Sn${}_{1-x}$)Se${}_2$ crystal confirmed by hexagonal structure having lattice parameters: $a=b=3.81\AA ,$ c = $6.14\AA$, and $\alpha =\beta =90^{\circ }$, $\gamma =120^{\circ }$ for x = 0. Optical parameters of layered crystals were characterized with optical absorption spectra within the wavelength range of 400 nm to 1100 nm. The thermal analysis of crystals have been performed by recording thermo gravimetric curve. The kinetic parameters, thermal activation energies evaluated by Broido method, Coast-Redfern method, Horowitz-Metzger method. The variation of electrical resistance with temperature shows that (In${}_x$Sn${}_{1-x}$)Se${}_2$ crystals have semiconducting behavior with negative temperature coefficient. Further, the activation energy has been decreased with Indium doping concentration increases in (In${}_x$Sn${}_{1-x}$)Se${}_2$ crystals. Also the photoresponse parameters are evaluated with 100 mw/cm${}^2$ illumination intensity of crystals.