High-Performance p-Type Quasi-Ohmic of WSe₂ Transistors Using Vanadium-Doped WSe₂ as Intermediate Layer Contact

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs), such as tungsten diselenide (WSe₂), hold immense potential for applications in electronic and optoelectronic devices. However, a significant Schottky barrier height (SBH) at the metal-semiconductor (MS) interface reduces the electronic device performance. Here, we present a unique 2D/2D contact method for minimizing contact resistance and reducing the SBH. This approach utilizes vanadium-doped WSe₂ (V-WSe₂) as the drain and source contacts. The fabricated transistor exhibited a stable operation with p-type quasi-ohmic contact and a high on/off current ratio surpassing 10⁸ at room temperature, reaching 10¹¹ at 10 K. The device achieved an on-current of 68.87 μA, a high mobility of 103.80 cm² V^-1 s^-1, a low contact resistance of 0.92 kΩ, and remarkably low SBH values of 1.51 meV for holes at V_GS = -120 V with fixed V_DS = 1 V. Furthermore, a Schottky photodiode has been fabricated, utilizing V-WSe₂ and Cr as the asymmetric contact platform, showing a responsivity of 116 mA W^1-. The findings of this study suggest a simple and efficient method for improving the performance of TMDC-based transistors.