Electric Field Induced Schottky to Ohmic Contact Transition in Fe₃GeTe₂/TMDs Contacts

Abstract

Although the two-dimensional transition metal dichalcogenides (TMDs) present excellent electrical properties, the contact resistance at the interface of metal/TMDs limits the device performance. Herein, we use 2D metallic Fe3GeTe2 (FGT) as an electrode in contact with TMDs semiconductors MX2 (M = Mo, W; X = S, Se, Te) and investigate the contact properties of FGT/MX2 based on density functional theory calculations. We demonstrated that FGT/MX2 presents n-type Schottky contacts, and their n-type Schottky barrier heights are lower than that of the most common bulk metal contacts with MX2, suggesting that FGT can be used as an efficient metallic electrode for MX2. The transitions from n-type Schottky contact to p-type Schottky contact and from Schottky contact to Ohmic contact can be achieved in FGT/MX2 under the electric field. This work not only illustrates an effective method to modulate the contact types and Schottky barrier heights of FGT/MX2 contacts but also provides a route for designing the nanodevices based on FGT/MX2 electrical contacts.

Tunable Schottky Barrier and Efficient Ohmic Contacts in MSi2N4 (M = Mo, W)/2D Metal Contacts

“…Compared with 3D metals, 2D metals can form vdW contacts with 2D semiconductors due to the absence of surface dangling bonds. − These vdW contacts involve weak interlayer interactions, which can weaken the MIGS and the interface dipoles between 2D metals and semiconductors. − As a result, the FLP effect can be significantly weakened, which will make SBH tunable. For instance, an extraordinarily low contact resistance (<0.1 kΩ·cm) has been observed in NbS 2 –MoS 2 FET, and the carrier mobility was 3 times higher than that of Mo-contacted MoS 2 -based FETs .…”

Ultralow Contact Resistance and Efficient Ohmic Contacts in MoGe2P4–Metal Contacts

“…Several strategies have been used to reduce the SBH, such as doping, applying electric fields, inserting a buffer layer, , and using 2D metals as electrodes. , For example, our previous study reported that the transition from Schottky contacts to Ohmic contacts can be found in Fe 3 GeTe 2 /MX 2 (M = Mo, W; X = S, Se, Te) by applying the external electric field . Recent works indicated that the tunable SBH can be realized in In 2 Ge 2 Te 6 and CrI 3 (CrBr 3 ) monolayers when using 2D metals as electrodes. , The insertion of graphene between monolayer BP and a bulk Ni electrode can increase the on-state current and improve the gate control ability .…”