Browsing by Author "Chien, Chung-Yen"

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Designer Ge Quantum-Dot Phototransistors for highly-integrated, broadband optical interconnects
(2016)
Kuo, Ming-Hao
;
Chien, Chung-Yen
;
Liao, Po-Hsiang
;
Lai, Wei-Ting
;
Li, Pei-Wen
We report high-responsivity Ge quantum dots (QDs) MOS phototransistors as on-chip transducers for highly-integrated, broadband Si-based optical interconnects. Self-organized heterostructure of Ge-QD/SiO2/Si-channel is fabricated in a single step through selective oxidation of SiGe nano-pillars over a Si3N4 buffer layer on Si substrates. Dark current densities (10(-7)A/mm(2)), photocurrent-to-dark current ratio (similar to 10(7)) and photoresponsivities (>10 A/W), external quantum efficiency (similar to 240%), and response time (1.4ns) are measured on the Ge-QD phototransistors under 850 nm illumination. Detection wavelength is tunable from near infrared to near ultraviolet by reducing the QD size from 90 to 7 nm, and the optimal photoresponsivity is tailored by the QD size and effective thickness of gate dielectrics.