Open AccessWaveguide-integrated microdisk light-emitting diode and photodetector based on Ge quantum dots
Author(s) -
Xuejun Xu,
Takuya Maruizumi,
Y. Shiraki
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.22.003902
Subject(s) - photodetector , optoelectronics , responsivity , materials science , optics , waveguide , quantum dot , light emitting diode , wavelength , diode , quantum efficiency , dark current , physics
Microdisk integrated with a bus waveguide is fabricated on silicon-on-insulator substrate containing Ge self-assembled quantum dots as active medium. The device is demonstrated to be operated as both light-emitting diode and photodetector. At forward bias, carriers are injected into the microdisk and light emission at 1.45-1.6 μm is extracted through the waveguide via microdisk-waveguide coupling. Sharp resonant peaks with Q-factor as high as 1350 are obtained in the electroluminescence spectra, corresponding to whispering gallery modes of the microdisk. At reverse bias, the device functions as a resonant cavity enhanced photodetector with wavelength-selective photo-response. The photo-current at resonant wavelength of 1533.65 nm is 50 times larger than that at non-resonant wavelength. The dark current density of the photodetector is as low as 0.29 mA/cm2 up to -10 V bias and the peak responsivity is 5.645 mA/W.