MXenes Contacts for p-type 2D Electronics

MXenes, a family of two-dimensional (2D) transition-metal carbides and nitrides, offer a compelling combination of metallic conductivity and tunable surface chemistry. However, their potential as electrical contacts for p-type 2D semiconductors remains largely untapped. Here, we systematically investigate the role of MXene composition by comparing Ti₃C₂T_x, Nb₂CT_x, and Mo₂CT_x as contacts for p-type 2H-MoTe₂ transistors. Through a polymer-assisted transfer process that ensures high-quality interfaces, we identify Nb₂CT_x as the best-performing contact material among the MXenes examined in this work, attributed to its superior band alignment, which markedly reduces contact resistance compared to both conventional metals and other MXenes. Consequently, Nb₂CT_x/2H-MoTe₂ field-effect transistors achieve a high hole mobility of approximately 17 cm²V^-1s^-1 and an on/off current ratio exceeding 10³. Temperature-dependent measurements further reveal a near-ideal interface, with a Schottky barrier height of only a few millielectronvolts under strong gate bias. These findings establish compositional engineering of MXenes as a powerful strategy for designing electrode-semiconductor interfaces and position Nb₂CT_x as a scalable, high-performance contact material for advancing p-type 2D electronics.