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Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe 2 /Pyramid Si Heterojunction
Author(s) -
Liang FengXia,
Zhao XingYuan,
Jiang JingJing,
Hu JiGang,
Xie WeiQiang,
Lv Jun,
Zhang ZhiXiang,
Wu Di,
Luo LinBao
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201903831
Subject(s) - responsivity , materials science , photodetector , optoelectronics , heterojunction , pyramid (geometry) , infrared , absorption (acoustics) , near infrared spectroscopy , sensitivity (control systems) , optics , physics , composite material , electronic engineering , engineering
In this study, a highly sensitive and self‐driven near‐infrared (NIR) light photodetector based on PdSe 2 /pyramid Si heterojunction arrays, which are fabricated through simple selenization of predeposited Pd nanofilm on black Si, is demonstrated. The as‐fabricated hybrid device exhibits excellent photoresponse performance in terms of a large on/off ratio of 1.6 × 10 5 , a responsivity of 456 mA W −1 , and a high specific detectivity of up to 9.97 × 10 13 Jones under 980 nm illumination at zero bias. Such a relatively high sensitivity can be ascribed to the light trapping effect of the pyramid microstructure, which is confirmed by numerical modeling based on finite‐difference time domain. On the other hand, thanks to the broad optical absorption properties of PdSe 2 , the as‐fabricated device also exhibits obvious sensitivity to other NIR illuminations with wavelengths of 1300, 1550, and 1650 nm, which is beyond the photoresponse range of Si‐based devices. It is also found that the PdSe 2 /pyramid Si heterojunction device can also function as an NIR light sensor, which can readily record both “tree” and “house” images produced by 980 and 1300 nm illumination, respectively.