Schottky Barrier Height Variation in MoTe₂/metal Junctions Studied by Spatially Resolved Photocurrent Measurement
K. C. Lee1*, L. C. Li2, Y. F. Lin1, T. S. Lin3, Y. W. Suen1
1Department of Physics, National Chung Hsing University, Taichung, Taiwan
2Center for Nano Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
3Department of applied physics, Tunghai University, Taichung, Taiwan
* presenting author:KUO-CHIH Lee,
The phase change induced the photocurrent variations near MoTe₂/metail Schottky barrier junctions are investigated by scanning photocurrent microscopy. We mapped out the photocurrent distribution of the p-type MoTe₂ TFT device, which is made of a 7.5-nm-thick by mechanically exfoliated flake and standard e-beam lithography process, by scanning a 633 nm-wavelength laser with a 1.5-μm spot size (power 400 μW). The results show that the photocurrent response is most significant near the MoTe₂/metal junctions and has a very large fluctuation along the junction boundary. The not uniform Raman mapping images of peak Ag(1T') near the junction demonstrate the fluctuation photocurrent is cause of partially phase convert from semiconducting (2H) into the metallic (1T') by high power laser irradiation. Moreover, the built-in potential can extracted from the bias dependence of the peak photocurrent and the variations is between 50 and 200 meV.

Keywords: MoTe2, scanning photocurrent microscopy, photovoltaic, phase conversion