Open AccessGourd-shaped hole array germanium (Ge)-on-insulator photodiodes with improved responsivity and specific detectivity at 1,550 nm
Author(s) -
Bongkwon Son,
Hao Zhou,
Yiding Lin,
Kwang Hong Lee,
Chuan Seng Tan
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.422931
Subject(s) - photodetector , responsivity , germanium , photodiode , optoelectronics , materials science , specific detectivity , optics , quantum efficiency , physics , silicon
Gourd-shaped hole array germanium (Ge) vertical p-i-n photodiodes were designed and demonstrated on a germanium-on-insulator (GOI) substrate with the excellent responsivity of 0.74 A/W and specific detectivity of 3.1 × 10 10 cm·Hz 1/2 /W. It is calculated that the gourd-shaped hole design provides a higher optical absorption compared to a cylinder-shaped hole design. As a result, the external quantum efficiency for the gourd-shaped hole array photodetector was enhanced by ∼2.5× at 1,550 nm, comparing with hole-free array photodetectors. In addition, the extracted specific detectivity is superior to that of commercial bulk Ge photodiodes. The 3-dB bandwidth for the hole array photodetectors is improved by ∼10% due to a lower device capacitance. This work paves the way for low-cost and high-performance CMOS compatible photodetectors for Si-based photonic-integrated circuits.