Efficient optical control of quantum tunneling devices based on layered violet phosphorus

Abstract

Electron tunneling devices attract attention due to their potential applications in integrated circuits, memories, and high-frequency oscillators. However, limited works are devoted to the optical control of electron tunneling processes. The main reason is the low concentration of photogenerated carriers concerning the equilibrium values in heavy-doped regions. In this work, violet phosphorus (VP) with a unique bilayer tubular structure supplies an excellent platform for investigating the tunneling mechanisms under photo illumination. A VP-based vertical tunneling diode made of metal-insulator-semiconductor (MIS) stacking is presented. The photogenerated carriers increase the tunneling current by ≈4.2 times through photo illumination, leading to a considerable rectification ratio. In addition, a three-terminal tunneling field-effect transistor (TFET) made from VP flake with different thicknesses is also presented. The interband tunneling of electrons results in a tunable negative differential transconductance (NDT) at room temperature. The photoillumination can modulate the onset of the NDT region due to the variation of the density of states with Fermi level alignment in the channel and drain region. These results advance the understanding of electron transport mechanisms in VP-based tunneling devices, showing great potential for exploiting novel 2D multifunctional devices with interactions between light and carriers’ tunneling.