TiO2-x-enhanced IR hot carrier based photodetection in metal thin film-si junctions
File(s)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
We investigate titanium nitride (TiN) thin film coatings on silicon for CMOS-compatible sub-bandgap charge separation upon incident illumination, which is a key feature in the vast field of on-chip photodetection and related integrated photonic devices. Titanium nitride of tunable oxidation distributions serves as an adjustable broadband light absorber with high mechanical robustness and strong chemical resistivity. Backside-illuminated TiN on p-type Si (pSi) constitutes a self-powered and refractory alternative for photodetection, providing a photoresponsivity of about ∼1 mA/W at 1250 nm and zero bias while outperforming conventional metal coatings such as gold (Au). Our study discloses that the enhanced photoresponse of TiN/pSi in the near-infrared spectral range is directly linked to trap states in an ultrathin TiO2–x interfacial interlayer that forms between TiN and Si. We show that a pSi substrate in conjunction with a few nanometer thick amorphous TiO2–x film can serve as a platform for photocurrent enhancement of various other metals such as Au and Ti. Moreover, the photoresponse of Au on a TiO2–x/pSi platform can be increased to about 4 mA/W under 0.45 V reverse bias at 1250 nm, allowing for controlled photoswitching. A clear deviation from the typically assumed Fowler-like response is observed, and an alternative mechanism is proposed to account for the metal/semiconductor TiO2–x interlayer, capable of facilitating hole transport.
Date Issued
2019-04-08
Date Acceptance
2019-04-01
Citation
ACS Photonics, 2019, 6 (4), pp.953-960
ISSN
2330-4022
Publisher
American Chemical Society
Start Page
953
End Page
960
Journal / Book Title
ACS Photonics
Volume
6
Issue
4
Copyright Statement
© 2019 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Photonics, after peer review and technical editing by the publisher. To access the final edited and published work see https:/dx.doi.org/10.1021/acsphotonics.8b01639
Sponsor
Engineering & Physical Science Research Council (E
The Leverhulme Trust
Engineering and Physical Sciences Research Council
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000465188900020&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
EP/M013812/1
RPG-2016-064
EP/M013812/1
Subjects
Science & Technology
Technology
Physical Sciences
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Optics
Physics, Applied
Physics, Condensed Matter
Science & Technology - Other Topics
Materials Science
Physics
hot carriers
TiN thin films
TiO2-x
sub-bandgap photodetection
CMOS compatible
REFRACTORY PLASMONICS
TIO2
GENERATION
EXCITATION
TRAPS
Publication Status
Published
Date Publish Online
2019-04-08