Dopingless Ambipolar Field-Effect Transistors Based on MoTe₂ 2D Material for CMOS Nanoelectronics

The charge transport characteristics of ambipolar MoTe₂ field-effect transistors (FETs), with the entire MoTe₂ channel exposed to ambient air, across varying temperature conditions, are experimentally and theoretically investigated. These FETs exhibit stable transport behavior without the need for complex surface encapsulation. This finding is significant as it eliminates the need for external and intentional n-type and p-type doping, addressing a major challenge in integrating 2D materials into complementary metal-oxide-semiconductor (CMOS) technology. The first-principles simulations provide insights into the electronic properties and band alignment at the Ni/MoTe₂ interface, revealing the fundamental mechanism behind the observed ambipolar transport response. Through temperature-dependent electrical characterization, hysteresis, threshold voltage shifts, and carrier mobility variations are investigated, providing a deeper understanding of MoTe₂/SiO₂ interface interactions. The results indicate that at elevated temperatures, charge trapping and phonon scattering lead to reduced carrier mobility and ON/OFF current ratio, which are primarily driven by interface interactions rather than material impurities. Importantly, the devices achieve stable performance despite direct exposure to ambient conditions, demonstrating their robustness without complex passivation techniques. Further optimization of passivation and encapsulation strategies can enhance performance, including carrier mobility improvement. This work demonstrates the potential of FETs based on MoTe₂, offering a promising pathway for next-generation CMOS nanoelectronics.