Gate Tunable Self-Biased Diode Based on Few Layered MoS2 and WSe2

The operation of a self-biased diode (SBD) based on MoS2 has been demonstrated by using an asymmetric top gate comprising metal-hexagonal boron nitride (h-BN)-MoS2 structure. The rectification is achieved by asymmetric modulation of effective Schottky barrier and carrier density in the channel during forward and reverse bias, and a rectification factor of 1.3 × 105 is achieved in I–V characteristics. The modulation of effective Schottky barrier is verified by temperature dependent measurement in a range of 173 to 373 K, and a difference of 300 meV is observed in effective Schottky barrier height for forward and reverse bias. The electrical characteristics of SBD exhibit close resemblance with an ideal thermionic emission model with an ideality factor of 1.3. SBD also exhibits strong photoelectrical response with a specific detectivity of 150 A/W and responsivity of 2.1 × 1010 Jones under 450 nm laser light illumination. In the end, to demonstrate the diversity of the proposed scheme, SBD based on WSe2 has also been fabricated and the results have been discussed. These results suggest a new route toward the SBD based numerous electronics and optoelectronics applications and can in principle be implemented using other two-dimensional materials as well.