Investigation of laser-induced-metal phase of MoTe2 and its contact property via scanning gate microscopy

Abstract

Although semiconductor to metal phase transformation of MoTe2 by high-density laser irradiation of more than 0.3 MW cm−2 has been reported, we reveal that the laser-induced-metal (LIM) phase is not the 1T′ structure derived by a polymorphic-structural phase transition but consists instead of semi-metallic Te induced by photo-thermal decomposition of MoTe2. The technique is used to fabricate a field effect transistor with a Pd/2H-MoTe2/LIM structure having an asymmetric metallic contact, and its contact properties are studied via scanning gate microscopy. We confirm that a Schottky barrier (a diffusion potential) is always formed at the Pd/2H-MoTe2 boundary and obstacles a carrier transport while an Ohmic contact is realized at the 2H-MoTe2/LIM phase junction for both n- and p-type carriers.