Surface plasmonic resonance induced near-field vectors and their contribution to quantum dot infrared photodetector enhancement

In this paper, we analyse surface plasmonic resonance (SPR) induced near-field electric-field vector distribution in the quantum dot (QD) region and determine their roles in quantum dot infrared photodetector (QDIP) enhancement. SPR can be excited in metallic two-dimensional subwavelength hole arrays (2DSHAs) when illuminated at resonant wavelengths. The SPR induced near-field vectors (Ez, Ex and Ey) and their distributions and overlaps with the QD active region are simulated. A long-wave infrared (LWIR) QDIP is fabricated with the 2DSHA plasmonic structure to experimentally measure the SPR enhancement spectrum and compare it with the near-field vector components and their distribution in QDs. We found that QDIP enhancement is closely related to the near-field intensity overlap integral in the QD region. The large near-field overlap integral corresponds to high QDIP enhancement. Such near-field overlap integral dependent plasmonic enhancement is attributed to the interaction of and the electric-dipole interaction in QDs.