Nonlinear Electrical Conductivity Properties of Au Films Prepared by Sputtering

Qingyun Meng,Ziwen Yin,Yixin Kang,Dongpeng Yan,Xiaoyu Zhai

doi:10.1155/2014/437082

Abstract

Metal-based films with tunable electrical conductivity have played an important role in developing new types of electric devices for future application. In this work, a sputtering method was used to obtain Au films on silicon substrate in a hypobaric atmosphere. Scanning electron microscope (SEM) shows that the interspaces between the Au nanoparticles were highly uniform and orderly distributed, with the width of several nanometers at the surface. By measuring theI-Vcurves of the films with thickness less than 20 nm, the nonlinear behaviors of electrical resistivity became gradually obvious as the decrease of the film thickness. For example, upon the thickness reducing to 10 nm, remarkable discontinuous step phenomenon appeared. Moreover, a computational simulation was carried on the electrical conductivity of films under normal temperature based on the Coulomb blockade theory and scattering theory, in which the electric current was in the range from 0 to 1.5 × 10−5 A. The computational results were consistent well with the experimental observations, which confirm that the nonlinear and step phenomenon can be assigned to the Coulomb blockade effect when electrons transfer occurs in the interspaces between the nanoparticles.

Highlights

In recent years, due to the rapid development of electric and electronic devices, extensive study has been focused on the interface behaviors of metal-metal and metal-semiconductor
Coulomb blockade phenomenon and macroscopic quantum tunneling phenomenon will play a significant role in the research and production of single electron device [8, 9], which will improve the degree of integration of integrated circuit
Under the temperature of 0.9 K, the systematic capacitance C would be less than 10−15 F order of magnitude, and the charging energy (EC = e2/2C) of a single electron would exceed the energy (KBT = 77.625 μeV) of electron’s thermal motion, which showed that thermal motion was covered up in low atmospheric pressure

Summary

Introduction

Due to the rapid development of electric and electronic devices, extensive study has been focused on the interface behaviors of metal-metal and metal-semiconductor. When the thickness of metal film was at the nanometer scale, the structures became discontinuous [3], which were composed of isolated nanoparticles; while the thickness of film was close to De Broglie wavelength, the energy level became in discrete state, and the motion of electrons was perpendicular to the surface of films, which presented quantum size effect [4, 5] In the latter case, the resistivity of film was very large, and the temperature coefficient of resistance (TCR) usually became a minus value, which presented Ohms feature at low electric field but presented non-Ohms feature [6, 7] at high electric field. By the combination of experimental and computational study on the discontinuous electrical conductivity of films, this work may pave an alternative way of metal films for further device application

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Results

Discussion

Conclusion