Defect Assisted Metal-TMDs Interface Engineering: A First Principle Insight

Abstract

2D materials make the scientific land more fertile to harvest future generation of high-performance electronic devices. Among these, TMDs are more promising for switching applications due to its band gap and stability over Graphene and Phosphorene respectively. Despite of these properties, performance of the TMDs FET is not achieved to its expectation yet due to high contact resistance at the metal-TMDs interfaces. Different metal-TMDs interfaces have been explored for contact resistance reduction [1] , [2] , [3] but, a systematic study of metal induced gap states [MIGS] for TMDs and corresponding engineering to improve the contact resistance is missing yet. To explore the gap, we have done systematic study of interaction of different metals ( Au, Cr, Ni and Pd ) with MoS 2 , MoSe 2 , WS 2 and WSe 2 followed by impact of chalcogen vacancy on corresponding interactions using Density Functional Theory (DFT). Chalcogen vacancy reduces all the metal-TMDs bond distance which can reduce corresponding contact resistance due to reduction in the tunneling barrier width. Defect engineering also converts intrinsic n-type Pd-TMDs contacts into p-type which can help in MoS 2 based CMOS circuit in future.