Abstract
We report on a photodetector in which colloidal quantum dots directly bridge nanometer-spaced electrodes. Unlike in conventional quantum-dot thin film photodetectors, charge mobility no longer plays a role in our quantum-dot junctions as charge extraction requires only two individual tunnel events. We find an efficient photoconductive gain mechanism with external quantum efficiencies of 38 electrons-per-photon in combination with response times faster than 300 ns. This compact device-architecture may open up new routes for improved photodetector performance in which efficiency and bandwidth do not go at the cost of one another.
Original language | English |
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Pages (from-to) | 5740-5743 |
Number of pages | 4 |
Journal | Nano Letters |
Volume | 12 |
Issue number | 11 |
DOIs | |
State | Published - Nov 14 2012 |
Externally published | Yes |
Keywords
- Colloidal quantum dots
- nanogap electrodes
- nanoscale photodetectors
- photoconductive gain