Electrical contacts of coplanar 2H/1T′ MoTe2 monolayer

Abstract

Contact resistance plays a crucial role in determining the performance of nanodevices. The phase contact of 2H/1T′ MoTe2 has driven significant interest for its potential in dealing with this issue. Using first-principles calculations, this work reports on the electronic and contact properties of coplanar 2H/1T′ MoTe2 interfaces down to monolayer limits. Twelve interface structures are investigated, two of them are expected to be the most energy-favored structures depending on the chemical condition; we name them as (0°, 30°) and (0°, −30°). For all the interfaces, the quality of electrical contact is evaluated by analyzing the Schottky barrier height (SBH), the interfacial states, and charge transfer at the phase boundaries. The SBH changes greatly between different interfaces. Especially, as the electrical contact of (0°, 30°) is ohmic with a small SBH of 0.03 eV for hole, the electrical contact of (0°, −30°) is Schottky with the Fermi level located near the midgap. All the interfaces introduce very tiny and thin midgap states in the 2H sides, these states cause the Fermi level to be partly pinned. Besides, linear band bending is found in these coplanar phase contacts due to interface polarity. Our results suggest that the control of interfacial morphology is a key factor for the device applications.