Open AccessInfrared broadband enhancement of responsivity in Ge photodetectors decorated with Au nanoparticles
Author(s) -
Liming Wang,
Wang Bo,
Yichi Zhang,
Lingyao Meng,
Hao Sun,
Tao Liu,
Ningning Zhang,
Zuimin Jiang,
Huiyong Hu
Publication year - 2021
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.423899
Subject(s) - responsivity , photodetector , materials science , photocurrent , optoelectronics , infrared , nanoparticle , visible spectrum , optics , wavelength , nanotechnology , physics
A broadband, high-performance infrared Ge photodetector decorated with Au nanoparticles (NPs) is proposed. Photoelectronic characterization demonstrated that the responsivity of devices decorated with Au NPs is as high as 3.95 A/W at a wavelength of 1550 nm. Compared with a Ge photodetector without Au NPs, the responsivity of a device decorated with Au NPs is significantly increased, i.e., by more than 10 times in the entire range of infrared communication wavelengths, including the O, E, S, C, L, and U bands. The increase is ascribed to type-II energy-band alignment between Ge covered with Au NPs and bare Ge, instead of the localized surface-plasmon-resonance effect. The type-II energy-band alignment enhances the spatial electron-hole separation and restrains the electron-hole recombination, thus a larger photocurrent is observed. These results reflect the potential of this approach for achieving broadband, high-performance Ge photodetectors operating in the near-infrared communication band.