Characterization of Metal Contacts to Two-Dimensional MoTe₂

Abstract

Transition metal dichalcogenide (TMD) atomic layers are an atomically thin material in the form of MX2, where M is a transition metal atom (such as Mo or W) and X is a chalcogen atom (such as S, Se, or Te). Among them, MoTe₂ is attractive because of its narrow band gap (i.e., ~ 1 eV), leading to optical and electrical applications such as field-effect transistors, photodetectors, lightemitting diodes, and photovoltaics. The TMD atomic layers, however, suffer from the extremely high contact resistance of the metal electrodes. The formation of a low-resistance ohmic contact is essential to achieving good device performance. Here, we examined the contact resistance of the two-dimensional MoTe₂ atomic tri-layers from transmission line model (TLM) measurements. 2H-phase MoTe₂ atomic tri-layers were synthesized on a silicon dioxide/silicon substrate by using metal-organic chemical vapor deposition. The TLM pattern was fabricated on the tri-layers to examine the specific contact resistance of metals. This method is highly effective for minimizing the contact resistance of TMD atomic layers.