Two Dimensional Crystal Tunneling Devices for THz Operation

TL;DR

This paper explores 2D crystal heterostructures as ultra-thin tunneling barriers for THz nonlinear devices, demonstrating their potential for high-frequency operation and applications in hot electron transistors.

Contribution

It introduces a novel use of 2D insulators as atomic-scale tunneling barriers, enabling THz operation with high nonlinearity and potential for active device applications.

Findings

Feasibility of diode operation with 2D barriers as thin as two monolayers.

Predicted cut-off frequencies over 10 THz.

Enhanced power performance in hot electron transistors.

Abstract

Two dimensional (2D) crystal heterostructures are shown to possess a unique opportunity for novel THz nonlinear devices. In contrast to the oxide tunneling barrier, the uniformity of 2D insulators in the thickness control provides an ideal condition for tunneling barriers in the atomic scale. Numerical calculations based on a first principles method clearly indicate the feasibility of diode operation with barriers as thin as two monolayers of hexagonal boron nitride or molybdenum disulfide when placed between graphene-metal asymmetric electrodes. Further analysis predicts the cut-off frequencies of the proposed device over 10 THz while maintaining strong nonlinearity for zero-bias rectification. Application of the tunneling structure to hot electron transistors is also investigated, illustrating the THz operation with superior power performance. The proposed concept provides an excellent opportunity for realizing active nonlinear devices in the frequency range inaccessible thus far.