Titanium Selenide
titanium selenide is a white, lustrous metal with a melting point of 1,660 degC and a density of 4.5 g/cc. It is used in a variety of products including watches, drill bits, and bicycles. It is also found in decorative, semiconductor, and optical coatings. It is usually evaporated in a vacuum for these applications. Titanium is biologically inert and is a non-toxic element. It is also non-reactive with water and air and has a low melting point.
A single molecular layer of titanium diselenide (TiSe2) reveals enhanced electronic properties beyond graphene--a key focus of current research. The material exhibits a small absolute bandgap at room temperature, with the bottom of the band gap being derived from the Ti 3d states. Angle-resolved photoemission spectroscopy measurements suggest that this band gap can be narrowed by symmetry breaking and phonon entropy effects. First-principles calculations and many-body perturbation theory support this interpretation.
A rapid, high-pressure (2 GPa) reaction method has been developed for the synthesis of single-crystalline TiSe2. The resulting material was characterized by X-ray diffraction and high resolution transmission electron microscopy. The structure was determined to be a hexagonal rod-like morphology. The new method provides a general route for the synthesis of other transition metal di-selenides. The materials are of interest for use as a three-dimensional interfacial layer between a high-mobility channel and a dielectric. These layers can be formed by atomic layer deposition (ALD) processes. The thin films are useful for the fabrication of metal-insulator-semiconductor (MIS) gates.
