The electrical characteristics and operation mechanism of a molybdenum disulfide/black phosphorus (MoS₂/BP) heterojunction device are investigated herein. Even though this device showed a high on-off ratio of over 1 × 10⁷, with a lower subthreshold swing of ~54 mV/dec and a 1fA level off current, its operating mechanism is closer to a junction field-effect transistor (FET) than a tunneling FET. The off-current of this device is governed by the depletion region in the BP layer, and the band-to-band tunneling current does not contribute to the rapid turn-on and extremely low off-current.
Keywords: 2D/2D heterojunction; MoS2; band-to-band tunneling (BTBT); black phosphorus; junction FET; tunneling FET; tunneling diode.