Charge Transport in Self-Assembled Metal Nanocrystal Array Devices
Abstract
We report on the fabrication of arrays of 3.8 nm CoPt3 nanocrystals between 70 nm gap electrodes by self-assembly. Variable temperature dc electrical characterization reveals that the electronic properties can be tuned in-situ using mild thermal annealing. Devices annealed at 80 ºC behave as Mott insulators with transport characteristics governed by charging energies of individual nanocrystals. Slightly higher anneal temperatures (100 ºC) result in quasi-metallic transport behavior with a transition from a negative temperature coefficient of resistance (TCR) at low temperatures to a positive TCR above 80 K. Devices annealed at 150 ºC show fully metallic transport characteristics. Thermal and structural analyses demonstrate that the nanocrystals are air-stable to 200 ºC, therefore the exponential increase in device resistivity with anneal temperature cannot be attributed to nanocrystal sintering. We believe this constitutes the first demonstration of an in-situ thermally induced insulator-metal transition in a self-assembled metal nanocrystal array.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARW36004Q