Defect-affected Photocurrent in MoTe2 FETs.

Imperfections in the crystal lattice, such as defects, grain boundaries, or dislocations, can significantly affect the optical and electrical transport properties of materials. In this study, we report the effect of mid-gap trap states on photocurrent in 10 atomic layered 2H-MoTe2. Our study reveals that the photocurrent is very sensitive to the number of active traps, which can be controlled by Vgs. By fitting the measured transient drain current, our estimation shows that the trap state density is approximately 5 × 1011 cm-2. By analyzing the photocurrent data as a function of gate voltage, we realize how the ionized traps affect the photoexcited carriers. The model of hole traps, electron traps, and recombination centers inside the bandgap successfully describes our observed results.