Microcavity coupled quantum dot emission with detuning control.

Abstract

Solution processed colloidal semiconductor quantum dots (QDs) have size-tunable optical transitions and high quantum efficiencies, enabling various applications in opto-electronic devices. To enrich the functionality of QD-based opto-electronic devices, colloidal semiconductor QDs have been frequently coupled with optical cavities to enable emission modulation. However, it remains a challenge to fully understand the interaction between the optical cavity resonance and the QD emission, especially for the planar optical microcavities. Here, we have investigated the light emission of colloidal semiconductor QDs in the planar Fabry-Perot microcavity consisted of two Ag mirrors. With the matched QD and cavity resonance, the microcavity coupled QD samples show a prominently narrower emission linewidth and emission angle range because of the efficient QD-cavity coupling, while with a slightly positive or negative energy detuning, the linewidth and angular distribution of the microcavity coupled QD emission both become broadened. Furthermore, with the standard lithography technique, the microcavity coupled QD sample can be patterned into arbitrary geometries, showing extra features of in-plane mode confinement. Our work highlights the important role of detuning in determining the coupling between colloidal semiconductor QDs and microcavities and paves the way for the future design of microcavity coupled QD devices.