Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor Based Diodes

TL;DR

This paper investigates the formation of Schottky barriers at graphene-semiconductor interfaces, revealing unique physics and potential applications in sensors and devices due to graphene's stability and electronic properties.

Contribution

It demonstrates the formation of Schottky barriers at graphene/semiconductor interfaces and models their electrical behavior using thermionic emission and Schottky-Mott theories.

Findings

Strong van der Waals attraction at interfaces

Charge transfer leads to rectifying barriers

Good agreement with theoretical models

Abstract

Using current-voltage (I-V) and capacitance-voltage (C-V) measurements, we report on the unusual physics and promising technical applications associated with the formation of Schottky barriers at the interface of a one-atom-thick zero-gap semiconductor (graphene) and conventional semiconductors. When chemical vapor deposited graphene is transferred onto n-type Si, GaAs, 4H-SiC and GaN semiconductor substrates, there is a strong van der Waals attraction that is accompanied by charge transfer across the interface and the formation of a rectifying (Schottky) barrier. Thermionic emission theory in conjunction with the Schottky-Mott model within the context of bond-polarization theory provides a surprisingly good description of the electrical properties. Applications, such as to sensors where in forward bias there is exponential sensitivity to changes in the Schottky barrier height due to the presence of absorbates on the graphene or to analogue devices for which Schottky barriers are integral components are promising because of graphene's mechanical stability, its resistance to diffusion, its robustness at high temperatures and its demonstrated capability to embrace multiple functionalities.