Open AccessSecond-order surface-plasmon assisted responsivity enhancement in germanium nano-photodetectors with bull’s eye antennas
Author(s) -
Fangfang Ren,
Weizong Xu,
Jiandong Ye,
KahWee Ang,
Hai Lu,
Rong Zhang,
Mingbin Yu,
GuoQiang Lo,
Hark Hoe Tan,
Chennupati Jagadish
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.015949
Subject(s) - responsivity , optics , photodetector , surface plasmon , germanium , materials science , optoelectronics , extraordinary optical transmission , grating , surface plasmon polariton , wavelength , ray , plasmon , physics , silicon
The enhancement of photo-response in nanometer-scale germanium photodetectors through bull's eye antennas capable of supporting 2nd-order Bloch surface plasmon modes is demonstrated in theory and experiment. A detailed numerical investigation reveals that the presence of surface wave and its constructive interference with the directly incident light are incorporated into the main mechanisms for enhancing transmission through the central nanoaperture. With a grating period of 1500 nm, the area-normalized responsivity can be enhanced up to 3.8 times at 2 V bias for a 780 nm laser. It provides an easier fabrication path for ultra-short wavelength operations especially in devices using optically denser materials.