Photocarrier Dynamics in MoTe2 Nanofilms with 2H and Distorted 1T Lattice Structures

Molybdenum telluride (MoTe 2 ), an emerging layered two-dimensional (2D) material, possesses excellent phase-changing properties. Previous studies revealed its reversible transition between 2 H and 1 T ' phases with a transition energy as small as 35 meV. Since 1 T '-MoTe 2 is metallic, it can serve as an electrical contact for semiconducting 2 H -MoTe 2 -based optoelectronic devices. Here, the photocarrier dynamics in MoTe 2 nanofilms synthesized by a one-step method and with coexisting multiple phases are investigated by transient absorption measurements. Both the energy relaxation time and the recombination lifetime of the excitons are shorter in the 1 T '-MoTe 2 compared to its 2 H phase. These results provide information on the different photocarrier dynamical properties of these two phases, which is important for future 2D optoelectronic and phase-change electronic devices based on MoTe 2 .