Tunable large-area phase reversion in chemical vapor deposited few-layer MoTe2 films†
Crystal phase-engineering of two-dimensional (2D) transition metal dichalcogenides (TMDs) shows remarkable potential for various electronic, optoelectronic and catalytic applications. Here, a few-layer 1T′–2H MoTe2 lateral homo-junction has been obtained by using a facile chemical vapor deposition (CVD) method. In this CVD growth process, the in-plane phase evolution of the MoTe2 film can be dynamically controlled via tuning the contact between the film and Te vapor. Moreover, a local large-scale reversible phase transition of MoTe2 film through heat treatment in a hydrogen atmosphere is reported. During this heat treatment, two types of phase transition from 1T′ to 2H are observed at 500 °C and 750 °C respectively. The mechanism of this reversible phase transition is analysed by first principles calculations. The fabricated 1T′–2H–1T′ homojunction devices demonstrate that the hole mobility of 2H-MoTe2 is comparable with the exfoliated samples. This work in dynamic phase control of MoTe2 provides a pathway to exploring structural transformation of 2D materials and manufacturing novel phase-change electronic devices.