Abstract
Quantum dots (QDs) have promising optoelectronic properties. Colloidal QD heterostructures, systems in which two semiconductors are incorporated in a single colloid, may show novel and potentially useful transport phenomena. Here, we report on the physical mechanisms of charge transport through PbSe-CdSe core shell QDs measured with cryogenic scanning tunneling spectroscopy. Compared to ...
Abstract
Quantum dots (QDs) have promising optoelectronic properties. Colloidal QD heterostructures, systems in which two semiconductors are incorporated in a single colloid, may show novel and potentially useful transport phenomena. Here, we report on the physical mechanisms of charge transport through PbSe-CdSe core shell QDs measured with cryogenic scanning tunneling spectroscopy. Compared to single-component QDs, an additional hole-induced electron tunneling channel is found. Electron tunneling with and without a hole occurs at different bias, allowing the determination of the electron hole interaction energy (80 meV). This energy is sufficiently large to allow for a transport regime at room temperature in which electrons tunnel into the dot only if a hole is present, an ideal situation for controlled single-photon emission.
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