Complementary split-ring resonator antenna coupled quantum dot infrared photodetector

Abstract

We present a study of the performance enhancement of a quantum dot infrared photodetector (QDIP), by means of complementary split-ring resonator (CSRR) nano-antennae. The QDIP is based on an asymmetric heterostructure containing a single layer of self-assembled InAs/GaAs quantum dots (QDs). The proximity of the QD plane to the top contact layer is exploited for the coupling with the near-field of the CSRR modes. The co-existence of the CSRR LC mode, at λLC = 7.4 μm, and of non-localized Bragg-like modes, is observed for the two-dimensional array of nano-antennae implemented on the QDIP. At λLC and a temperature T = 10 K, the antenna coupled device is characterized by a responsivity of 44 μA/W and a specific detectivity D* = 1.5 × 108Jones. For the highly localized LC mode, enhancements of a factor 1.7 in responsivity and 2.1 in specific detectivity are observed. Within the sub-wavelength LC mode effective surface, normalizing the overall response to the active surface of the detector, a responsivity enhancement of ∼19 is estimated, showing the potentiality of this approach for the realization of high-performance QDIPs working at normal incidence.