Highly n-doped germanium-on-insulator microdisks with circular Bragg gratings.
Opt Express
; 25(6): 6550-6560, 2017 Mar 20.
Article
en En
| MEDLINE
| ID: mdl-28381002
We demonstrate germanium (Ge) microdisks surrounded by highly reflective circular Bragg gratings on highly n-doped germanium-on-insulator (GOI) substrate. The GOI substrate is fabricated by wafer bonding from Ge grown on Si substrate, and n-type doping concentration of 2.1×1019 cm-3 is achieved by phosphorus diffusion from a spin-on-dopant source. Very sharp Fabry-Perot resonant peaks with high contrast fringes and Q-factors up to 400 are observed near the direct band gap of Ge in photoluminescence spectra. The reflectivity of gratings are enhanced by a factor larger than 3 in a wide wavelength range from 1.57 to 1.82 µm, compared with that of Ge/SiO2 interfaces in normal microdisks without circular Bragg gratings. The surface emission intensity of the devices is found to be increased by the grating period. Our results indicate that GOI microdisk with circular Bragg grating is a promising optical resonator structure suitable for realizing low threshold, compact Ge lasers integrated on Si substrate.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
Opt Express
Asunto de la revista:
OFTALMOLOGIA
Año:
2017
Tipo del documento:
Article
Pais de publicación:
Estados Unidos