Titanium dichalcogenides: from synthesis to 2D Device Fabrication

Abstract

Titanium based dichalcogenides attract interest due to interesting electronic properties. TiTe2 material is semi metallic in nature with overlap of valence and conduction bands and TiSe2 is a low band gap semiconductor. The appearance of electronic phase transitions like (CDW, Superconductivity) in recent researches1-2 also attracts lot attention and interests to the research community towards this material. This project presents fabrication methods like Chemical Vapour Transport (CVT) and the determination of the necessary parameters for the synthesis of the high-quality single crystals of TiTe2 and TiSe2. These crystals are characterized by different techniques like XRD, SEM and EDXA to ensure the quality of the crystals. These Crystals are further exfoliated using exfoliation technique as anodic bonding technique and chemical exfoliation technique to get monolayer or very thin layer of these materials. Anodic bonding technique emerges as an efficient and easy technique alternative to scotch tape exfolaition. Few layers samples with large area and high quality such as graphene and other 2D semiconductors like MoS2, GaS NbSe2 has been successfully reported by the lab using this method.3-5 The samples are characterized with Raman spectrocopy and thickness is measured with AFM. A detailed Raman study is further done to test the integrity of few layer sample of TiSe2. These thin layer samples further will be used to study the electronic properties of the sample by applying the efficient space charge doping technique used by our lab to change their electronic properties and to induce electronic phase transitions.