Open AccessSurface illuminated interdigitated Ge-on-Si photodetector with high responsivity
Author(s) -
Yuxuan Li,
Xiaobin Liu,
Xuetong Li,
Shuai Wang,
Yu Han,
Lanxuan Zhang,
Yingzhi Li,
Shanhui Sun,
Baisong Chen,
Yao Ma,
Pengfei Guo,
Fengli Gao,
Xueyan Li,
GuoQiang Lo,
Jun-Feng Song
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.427343
Subject(s) - responsivity , photodetector , dark current , materials science , optoelectronics , germanium , avalanche photodiode , optics , photodiode , silicon , detector , biasing , voltage , physics , quantum mechanics
To address the problem of traditional surface illuminated detectors being of low responsivity, this work proposes a large-size interdigitated "finger-type" germanium-on-silicon (Ge-on-Si) photodetector (PD) based on the surface illumination approach. For 1550 nm light with a surface incident power of -20 dBm at room temperature, the best responsivity of the PD achieved is ∼0.64 A/W at 0.5 V. At the same time, the optimal bandwidth reaches 1.537 MHz with 3.5 V applied voltage. In order to suppress the dark current induced noise, a Ge-on-Si avalanche photodiode (APD) with the interdigitated structure is designed. The avalanche voltage is designed ∼13.3 V at room temperature, and the dark current density in linear region is at mA/cm 2 order. We believe this type of device can be applied in weak light detection condition.