Barre 12-22 426
Augustin Caillas – James Franck Institute, The University of Chicago
Abstract
As the field of colloidal quantum dot (CQD) optoelectronics advances rapidly, enhancing light-matter interactions within these systems has become a key focus to improve device performance, boost efficiency, and enable advanced functionalities. In recent years, various optically resonant architectures—such as cavities, plasmonic structures, and gratings—have been proposed. Here, we explore strategies that integrate plasmonic antennas with HgTe CQDs to design enhanced devices for infrared photodetection and emission applications. We present a photoconductor device based on a metal-insulator-metal structure which provide a 15-fold increase to specific detectivity within a narrow spectral band centered at 3.8 microns, achieving a peak spectral detectivity of 9 x 109 Jones at room temperature. This design can be easily adapted to cover different regions of the infrared, notably the long-wave infrared where absorption enhancement is crucial to compensate for the low extinction coefficient of the CQDs. In addition to improved photodetection, the architecture enhances the luminescence of the CQD film, benefiting emission devices. This enhancement is utilized to boost the performance of a HgTe CQD planar cascade LED, achieving a quantum efficiency of 4.4% and a power efficiency of 0.036% for an emission peak at 6.25 µm. The design benefits from the highly localized optical modes associated with plasmonic resonators which confine the field to a small portion of the device area. As a consequence, the plasmonic antennas can also be used as a tool to shape the spatial distribution of the electric field within the CQD film, which we exploit to reduce the noise of photodetectors.
