The work in this book is based on experimental aspects. Here author describes the growth as well as some characterizations of tin monoselenide and tin monosulphide single crystals. The large sized single crystals of SnSe and SnS were successfully grown by direct vapor transport technique without any transporting agent. The stoichiometries of constituent elements in the crystals were confirmed from the EDAX analysis. The results from the X-ray diffraction analysis indicate orthorhombic crystal structure of the crystals. The microscopic examinations of the surfaces of the crystals have revealed layered growth mechanism for their growth. The positive value of the hall coefficient and Seeback coefficient indicate that both the types of crystals are of p- type and majority charge carriers in them are holes. The optical absorption study has clearly shown that SnX (X=S, Se) compounds have direct as well as indirect band gaps. The electrical resistance of tin monoselenide and tin monosulfied was found to be pressure dependent. No transition in the resistance was observed for these crystals up to 6 GPa.

Transition metal dichalcogenides have been extensively studied during last two decades. These materials range from insulators to conductors and have a diversity of properties including charge density waves, superconductivity, activity and a rich intercalation chemistry. Tungsten Dichalcogenides find a wide range of applications in the field of catalysis and as a lubricant at high temperature and pressure.WTe2 has been widely used for solar energy conversion in Photoelectrochemical (PEC) solar cell due to small band gap and high chemical stability.