Development of step junction for molecular electronics

Jaewon Choi, Purdue University

Abstract

A novel device structure for molecular electronics using a nanometer scale gap, which is made only by conventional micro-scale fabrication techniques is presented. The gap is fabricated without e-beam lithography using the sidewall of positive photoresist profile. Generally, the gap size is a few tens of nm, but can approach ∼1 nm, which is the size of simple organic molecules, because of process variation. Electrical conduction through short organic molecules is demonstrated with gate modulation and temperature dependency in this study. Using a silicon dioxide layer underneath of the gap as gate insulator, three terminal devices with organic molecules are constructed with or without the help of gold clusters and this structure can be an effective tool for exploring molecular conduction. The two contacts to molecules can have different metals, unlike conventional break junction techniques. This advantage can supply a controllable way to make unequal coupling to molecules and finally to make rectifying devices. Also, it is possible to show clear quantum effect of molecular conduction even at room temperature because of reduced energy level broadening in molecular electron energy spectrum. The application to highly sensitive and selective chemical sensors, highly conductive organic field effect transistors, nanoscale organic light emitting diodes, and nano-lithography without e-beam writing will be discussed based on this novel structure. A potential way to fabricate integrated circuits of molecular devices with this novel structure will be also given in this study.

Degree

Ph.D.

Advisors

Janes, Purdue University.

Subject Area

Electrical engineering|Molecules

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