TiO2–x-Enhanced IR Hot Carrier Based Photodetection in Metal Thin Film–Si Junctions

• DOI: 10.1021/acsphotonics.8b01639
• Publication Date: 2019-04-08T17:04:33Z
• Authors: Nicholas A. Güsken; Alberto Lauri; Yi Li; Takayuki Matsui; Brock Doiron; Ryan Bower; Anna Regoutz; Andrei Mihai; Peter K. Petrov; Rupert F. Oulton; Lesley F. Cohen; Stefan A. Maier
• Keywords: Photodetection; Photocurrent

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 tunable oxidation distributions serves as an adjustable broadband light absorber with high mechanical robustness strong chemical resistivity. Backside-illuminated TiN p-type Si (pSi) constitutes self-powered refractory alternative photodetection, providing photoresponsivity about ∼1 mA/W at 1250 nm zero bias while outperforming conventional metal such gold (Au). Our study discloses that enhanced photoresponse TiN/pSi near-infrared spectral range directly linked to trap states ultrathin TiO2–x interfacial interlayer forms between Si. show pSi substrate conjunction few nanometer thick amorphous can serve platform photocurrent enhancement various other metals Au Ti. Moreover, TiO2–x/pSi be increased 4 under 0.45 V reverse nm, allowing controlled photoswitching. A clear deviation from typically assumed Fowler-like response observed, mechanism proposed account metal/semiconductor interlayer, capable facilitating hole transport.