Fabrication of single-electron transistors with electromigrated Ni nanogaps

Mitsuki Ito,Jun-Ichi Shirakashi,Mamiko Yagi

doi:10.1063/1.5031822

Mitsuki Ito, Jun-Ichi Shirakashi + Show 1 more

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https://doi.org/10.1063/1.5031822

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Abstract

We analyze single-electron transistors (SETs) fabricated with electromigrated Ni nanogaps using the Korotkov and Nazarov (KN) model. First, we investigate nanogap-based SETs consisting of multiple Ni islands placed between the source and drain electrodes by a field-emission-induced electromigration technique known as “activation.” After the activation procedure is performed using a preset current Is of 3 μA, the drain current-drain voltage characteristics of SETs with single-island structures are obtained and analyzed by using the KN model and considering the offset charges on the islands. We determine the fitting parameters obtained by the KN model from the electrical properties of the SETs. The parameters can be explained using the geometrical structures of the SETs that are observed in both scanning electron and atomic force microscopy images after the activation procedure. This approach allows the electrical and structural properties of the single-island structures of the SETs fabricated using the activation method to be determined.

Highlights

The single-electron transistor (SET) is a nanoscale transistor that operates under single-electron transport through both coulomb islands and electrodes
Our research group has previously achieved the fabrication of SETs by using electromigration that was induced by field emission currents flowing through the nanogaps, referred to as “activation.”[10,11,12,13,14] In addition, we found that the number of islands formed during the formation of the SETs can be controlled by the magnitude of the preset current used in the activation procedure.[13,14]
We evaluated the single-island structures of nanogap-based SETs fabricated using electromigration induced by a field emission current, a process referred to as “activation.” After performing activation with a preset current of Is ranging from 500 nA to 700 nA, the device’s coulomb blockade voltage was clearly modulated non-periodically by the gate voltage V G

Summary

INTRODUCTION

The single-electron transistor (SET) is a nanoscale transistor that operates under single-electron transport through both coulomb islands and electrodes. It is important to consider the geometrical structures of singleelectron devices when manipulating single-electron charges.[1] the coulomb islands must be arranged precisely to obtain reproducible single-electron phenomena in practice. We discuss the experimental analysis we utilized to obtain accurate circuit parameters for single-dot SETs. Nanogap-based SETs with single islands are fabricated using the activation method, and they exhibit clear coulomb diamonds at 18 K. Nanogap-based SETs with single islands are fabricated using the activation method, and they exhibit clear coulomb diamonds at 18 K Their electrical circuit parameters, including their offset charges Q0, are analyzed by applying the orthodox model

EXPERIMENT DETAILS

RESULTS AND DISCUSSION

CONCLUSION