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Proceedings Paper

Surface engineering using compounds of titanium nanocoatings for silicon-based optical devices
Author(s): Ankitha E. Bangera; Kumar Appaiah; Subhananda Chakrabarti
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Paper Abstract

Most silicon based detectors are sensitive predominantly in the visible region. To extend their sensitivity further into the UV and IR regions, surface modification techniques can be employed. In addition, there is always a need for biocompatible, eco-friendly, and cost effective devices for bio-medical applications. Therefore, devices fabricated using silicon and titanium can enable the fabrication of affordable health care devices. Another critical factor that plays a major role in controlling the device performance is its surface wettability. Tuning the surface energy and thus its wettability can improve the stability, passivation, self-cleaning, and anti-aging properties of device surfaces. In this paper, we present a method for tuning the surface wettability with enhanced optical absorption in the UV-Vis-NIR regions. We optimize the titanium coatings on silicon substrates and demonstrate how the controlled deposition of film thickness and annealing temperature or time can affect the self-cleaning behavior and light localization with anti-reflection properties of surfaces. We take the combined advantage of the anti-reflective properties of anatase or rutile phases of oxides of titanium (TiOx) and the nature of opto-semiconductor Schottky barrier Ti-O-Si formed at the titanium and silicon interface for the improved absorption in a wide spectral range of radiation ranging from 200 nm (UV) to 3000 nm (short-wavelength infrared) wavelengths. An average optical reflectance tuned to less than 10% and absorbance greater than 70% can be obtained. Further, these coatings act as a protective encapsulation by possessing a hydrophobic surface with water contact angles < 100°.

Paper Details

Date Published: 1 March 2019
PDF: 13 pages
Proc. SPIE 10919, Oxide-based Materials and Devices X, 1091926 (1 March 2019); doi: 10.1117/12.2506678
Show Author Affiliations
Ankitha E. Bangera, Indian Institute of Technology Bombay (India)
Kumar Appaiah, Indian Institute of Technology Bombay (India)
Subhananda Chakrabarti, Indian Institute of Technology Bombay (India)

Published in SPIE Proceedings Vol. 10919:
Oxide-based Materials and Devices X
David J. Rogers; David C. Look; Ferechteh H. Teherani, Editor(s)

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