First-Principles Study of the Contact Resistance at 2D Metal/2D Semiconductor Heterojunctions

Abstract

The high contact resistance at metal/two-dimensional (2D) semiconductor junctions is a major issue for the integration of 2D materials in nanoelectronic devices. We review here recent theoretical results on the contact resistance at lateral heterojunctions between graphene or 1T-MoS2 with 2H-MoS2 monolayers. The transport properties at these junctions are computed using density functional theory and the non-equilibrium Green’s function method. The contact resistance is found to strongly depend on the edge contact symmetry/termination at graphene/2H-MoS2 contacts, varying between about 2 × 102 and 2 × 104 Ω∙μm. This large variation is correlated to the presence or absence of dangling bond defects and/or polar bonds at the interface. On the other hand, the large computed contact resistance at pristine 1T/2H-MoS2 junctions, in the range of 3–4 × 104 Ω.μm, is related to the large electron energy barrier (about 0.8 eV) at the interface. The functionalization of the metallic 1T-MoS2 contact by various adsorbates is predicted to decrease the contact resistance by about two orders of magnitude, being very promising for device applications.

Van der Waals‐Interface‐Dominated All‐2D Electronics

“…Furthermore, the 2D metal/semiconductor vdW interfaces avoid the damage of evaporation to the channel and inhibit the DIGS. [ 95 ] Therefore, the 2D metal/semiconductor vdW interfaces can be effectively tuned to the Schottky barrier due to the weak FLP. The carrier transport characteristics of electronics can be regulated and the R C can be reduced.…”

Featuring the State of the Art of Nanosciences in Belgium

“…First-principle computational techniques based on density functional theory have been used by Houssa et al [3] to predict the current-voltage characteristics of lateral junctions between graphene and 2H-MoS 2 and also 1T-MoS 2 and 2H-MoS 2 . Both systems are examples of conducting-semiconducting 2D heterostructures.…”

Assessing the role of quantum effects in two-dimensional heterophase MoTe2 field effect transistors

“…Ab-initio and first-principles-based methods have been extensively used to model 2D material-based devices during recent years [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. In our previous work [31], we have used ab-initio calculations to demonstrate how interface resonances at ML T -H MoTe 2 contacts create peaks in the transmission such that the Schottky barrier heights extracted by the thermionic emission model yield significantly different results than the Schottky barrier seen in the density of states (DOS).…”