Improved electrical properties of encapsulated MoTe2 with 1T′ edge contacts via laser irradiation

Abstract

Transition metal dichalcogenides (TMDCs) encapsulation is an essential technology for improving electron transport and preventing external contamination in practical applications. Nevertheless, Ohmic contacts in TMDCs continue to pose many problems. A laser was irradiated along with MoTe2 encapsulated in h-BN and edge contact electrodes. We studied the properties of the edge contact resistance, in which the crystal structure of MoTe2 changes from a semiconductor hexagonal phase (2H) to a metallic monoclinic phase (1T′). The contact between TMDCs and the metal electrode, Fermi-level pinning, contact resistance, and Schottky barrier height (SBH) can be calculated. Laser irradiation of the edge contact confirmed that, due to the change in the crystal structure of MoTe2, a reduction in contact resistance by over a factor of three resulted in the development of the electrical properties of the device. Field-effect transistors (FETs) with indium (In) edge contact exhibit high performance, with the highest electron mobility reaching 7.9 cm2V−1s−1 at 300 K. Furthermore, the barrier heights for In with a MoTe2 junction were 10.3 meV after laser irradiation, which is more than ten times the low SBH. This study confirms the improved electrical properties of the two-dimensional material and metal were confirmed using a laser.