Evanescent waveguide modes in subwavelength hole arrays and their role in enhancing the performance of quantum dot infrared photodetectors.

摘要

Accumulated strain existing in multi-stacked Quantum Dot layers has been a major issue for the Quantum Dot Infrared Photodetectors (QDIPs), which limits the number of layers that can be grown for the device. This inherent character leads to a thin active region which is only able to interact with a small percentage of infrared energy inside the detector. In this thesis, a metallic two dimensional subwavelength hole array was integrated on the QDIPs; photocurrent enhancement of the QDIPs was observed at different plasmonic resonance wavelengths: enhancement ratio and its dependence on the hole diameter was investigated; evanescent waveguide mode and its impact on near field transmission was analyzed by changing the dimension of the hole. Finally, the performance (photocurrent, responsivity, detectivity) improvement was observed and reported.