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Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
Published on: December 5, 2015
Enhanced semiconductor nanocrystal conductance via solution grown contacts
Matthew T Sheldon1, Paul-Emile Trudeau, Taleb Mokari
1University of California, Berkeley, California 94720, USA.
Nano Letters
|August 21, 2009
Summary
Direct growth of gold tips on cadmium selenide (CdSe) nanorods dramatically increased conductance by 100,000-fold. This enhancement stems from a significantly reduced interface barrier, improving nanorod device performance.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Electrical contacting of individual nanorods is crucial for nanoscale electronic devices.
- Achieving low-resistance contacts is a significant challenge in nanorod-based electronics.
Purpose of the Study:
- To develop an improved method for electrically contacting cadmium selenide (CdSe) nanorods.
- To investigate the impact of direct gold (Au) tip growth on CdSe nanorod conductance.
- To understand the mechanism behind the observed changes in electrical properties.
Main Methods:
- Direct solution-phase growth of Au tips on CdSe nanorod ends.
- Measurement of conductance in individual CdSe nanorods before and after Au tip growth.
- Utilizing ultraviolet-visible (UV-vis) spectroscopy and X-ray photoelectron spectroscopy (XPS) to analyze material composition.
- Conducting low-temperature tunneling and high-temperature (250-400 K) thermionic emission measurements.
Main Results:
- A 100,000-fold increase in conductance was observed for CdSe nanorods with direct Au tip contacts.
- Spectroscopic analyses confirmed that the enhancement is not due to alloying between Au and CdSe.
- Electrical measurements revealed a 75% reduction in the interface barrier to conduction compared to control samples.
- The barrier lowering was correlated with the electronic structure at the Au-CdSe interface.
Conclusions:
- Direct solution-phase growth of Au tips provides a highly effective method for contacting CdSe nanorods.
- The improved contact significantly lowers the interface barrier, leading to a dramatic increase in conductance.
- Nanocrystal surface structure plays a critical role in achieving robust device performance.
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