Phase patterning for ohmic homojunction contact in MoTe 2

• DOI: 10.1126/science.aab3175
• Publication Date: 2015-08-06T19:00:13Z
• Authors: Suyeon Cho; Sera Kim; Jung Ho Kim; Jiong Zhao; Jinbong Seok; Dong Hoon Keum; Jaeyoon Baik; Duk-Hyun Choe; K. J. Chang; Kazu Suenaga; Sung Wng Kim; Young Hee Lee; Heejun Yang
• Keywords: Homojunction; Ohmic contact

Artificial van der Waals heterostructures with two-dimensional (2D) atomic crystals are promising as an active channel or a buffer contact layer for next-generation devices. However, genuine 2D heterostructure devices remain limited because of impurity-involved transfer process and metastable inhomogeneous formation. We used laser-induced phase patterning, polymorph engineering, to fabricate ohmic heterophase homojunction between semiconducting hexagonal (2H) metallic monoclinic (1T') molybdenum ditelluride (MoTe2) that is stable up 300°C increases the carrier mobility MoTe2 transistor by factor about 50, while retaining high on/off current ratio 10(6). In situ scanning transmission electron microscopy results combined theoretical calculations reveal Te vacancy triggers local transition in MoTe2, achieving true device contact.