Single PbS colloidal quantum dot transistor

Abstract Control and understanding of the carrier transport in colloidal quantum dots (CQDs) is crucial for device applications. However, due to the fluctuations in the size and morphology of CQD arrays, characterizing carrier transport has been challenging. In this work, we investigated the carrier transport through a single oleic acid-capped PbS CQD coupled to nanogap metal electrodes. We measured single electron tunneling through the CQDs and observed quantum dot size-dependent carrier transport, a large charging energy, orbital-dependent electron charging energy and conductance, electric field modulation of the electron confinement potential, and the Kondo effect, which provide nanoscopic insights into the carrier transport through CQDs at the single quantum dot level. These findings as well as the commercial availability and high stability make PbS CQDs promising for future development of optoelectronic and quantum information devices, particularly room-temperature single-electron transistors with excellent optical properties.