Nanoscale plasmonically enhanced photodetector based on a gold nanoring.

Applied optics

PubMedID: 28157901

Safaee SM, PilAli A, Karami MA. Nanoscale plasmonically enhanced photodetector based on a gold nanoring. Appl Opt. 2017;56(3):476-481.
A nanoscale germanium-gold Schottky photodetector (PD) is proposed based on a nanoring supporting localized surface plasmon excitation. A design methodology is presented based on maximizing resonant transmission power throughput of light from the active region of the PD. Numerical calculations show significant field enhancement of about 200 times in the near-field zone inside of the nanoring, which is utilized to compensate the responsivity decrease due to PD active region volume shrinkage, providing the responsivity of 338??mA/W at a 1310 nm detection wavelength. In addition, the incident wavelength is detected in about one-seventh of the absorption length of bulk germanium, yielding about 33% of the external quantum efficiency. The ratio of responsivity to the active region volume of the PD is calculated to be approximately 100 times that of similar studies.