Fast and efficient photodetection in nanoscale quantum-dot junctions

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.

References in corpus (4)

• High Efficiency Carrier Multiplication in PbSe Nanocrystals: Implications for Solar Energy
• Simultaneous measurements of electronic conduction and Raman response in molecular junctions
• Nanogaps with very large aspect ratios for electrical measurements
• Controlling Nanogap Quantum Dot Photoconductivity through Optoelectronic Trap Manipulation

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• Dynamical photo-induced electronic properties of molecular junctions