Quantum selection rule dependent plasmonic enhancement in quantum dot infrared photodetectors

摘要

In this paper, we analyze quantum selection rules of intersubband transitions in quantum dots (QDs) and determine their impact on plasmonic enhancement in quantum dot infrared photodetectors (QDIPs). Photoluminescence and photocurrent spectrum measurement were performed on QD samples with different doping levels to identify the QD energy levels and associate the photodetection peaks with the intersubband transitions. The quantum selection rules of the intersubband transitions are determined by the electric-dipole interaction. To determine the impact of quantum selection rules on the plasmonic enhancement, we fabricated metallic two-dimensional subwavelength hole array (2DSHA) plasmonic structures with different periods on QDIPs for specific plasmonic enhancement of individual intersubband transitions. We found that the plasmonic enhancement ratios of different intersubband transitions are not the same. The unequal enhancement ratios are attributed to the quantum selection rules in the intersubband transitions and the dominant electric field (E-field E) vectors induced by the 2DSHA plasmonic structure.