Synthesis and characterization of the ultra-thin SnS flakes and the micron-thick SnS crystals by chemical vapor deposition

Stannous sulfide (SnS) was grown on SiO2/Si substrates via chemical vapor deposition technique and characterized using optical microscopy, scanning electronic microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, atomic force microscopy and photoluminescence (PL) spectrum, respectively. The results indicate that SnS with two distinct morphologies of the ultra-thin SnS flakes and the micron-thick SnS crystals can be grown on different zones of the SiO2/Si substrate. The ultra-thin SnS flakes are single crystal with thickness of 139nm and maximum lateral sizes of 371m. However, the micron-thick SnS crystals are 2.2m-thick and a lateral size of 15m with square shape. The difference in morphology between the ultra-thin SnS flakes and the micron-thick SnS crystals is mainly due to the difference in the initial nucleation way. Both theultra-thin SnS flakes and the micron-thick SnS crystals are orthorhombic structure with high-purity. PL strong peak of the ultra-thin SnS flakes is at 950nm, and it is at 945nm for the micron-thick SnS crystals. Their optical band gap isapproximately 1.31eV.