Temperature dependent transport characteristics of graphene/n-Si diodes

TL;DR

This study investigates the temperature-dependent electrical transport properties of graphene/n-Si Schottky diodes, highlighting the effects of interface inhomogeneities and providing quantitative analysis of barrier height fluctuations.

Contribution

It presents a detailed experimental analysis of graphene/n-Si diodes, including fabrication, electrical characterization, and a quantitative model for interface inhomogeneities.

Findings

High rectification ratio (>10^6) with minimal reverse leakage current (<10^-10 A)

Schottky barrier heights of 0.69 eV (exfoliated) and 0.83 eV (CVD) at room temperature

Temperature dependence indicates interface inhomogeneities affecting transport

Abstract

Realizing an optimal Schottky interface of graphene on Si is challenging, as the electrical transport strongly depends on the graphene quality and the fabrication processes. Such interfaces are of increasing research interest for integration in diverse electronic devices as they are thermally and chemically stable in all environments, unlike standard metal/semiconductor interfaces. We fabricate such interfaces with n-type Si at ambient conditions and find their electrical characteristics to be highly rectifying, with minimal reverse leakage current ($<$10$^{-10}$ A) and rectification of more than $10^6$. We extract Schottky barrier height of 0.69 eV for the exfoliated graphene and 0.83 eV for the CVD graphene devices at room temperature. The temperature dependent electrical characteristics suggest the influence of inhomogeneities at the graphene/n-Si interface. A quantitative analysis of the inhomogeneity in Schottky barrier heights is presented using the potential fluctuation model proposed by Werner and G\"{u}ttler.