Next Article in Journal
Composition versus Wear Behaviour of Air Plasma Sprayed NiCr–TiB2–ZrB2 Composite Coating
Next Article in Special Issue
Preparation and Spectrum Characterization of a High Quality Linear Variable Filter
Previous Article in Journal
IRI Sensitivity to the Influence of Surface Distress on Flexible Pavements
Previous Article in Special Issue
Investigation of TiO2 Thin Film Deposited by Microwave Plasma Assisted Sputtering and Its Application in 3D Glasses
Open AccessArticle

Automated Control of Plasma Ion-Assisted Electron Beam-Deposited TiO2 Optical Thin Films

School of OptoElectronic Engineering, Changchun University of Science and Technology, Changchun 130012, China
Scottish Universities Physics Alliance (SUPA), The Institute for Thin Films, Sensors & Imaging, University of the West of Scotland, Paisley PA1 2BE, UK
CJS Instrumentation Ltd., Easter Inch Industrial Estate, Bathgate EH48 2FJ, UK
Scottish Universities Physics Alliance (SUPA), Department of Biomedical Engineering, University of Strathclyde, Glasgow G1 1QE, UK
Authors to whom correspondence should be addressed.
Coatings 2018, 8(8), 272;
Received: 4 July 2018 / Revised: 20 July 2018 / Accepted: 3 August 2018 / Published: 5 August 2018
(This article belongs to the Special Issue Applications of Optical Thin Film Coatings)
PDF [3829 KB, uploaded 5 August 2018]


A hollow cathode plasma source has been operated automatically, demonstrating independent control of plasma ion energy and ion current density for plasma ion-assisted electron beam-deposited titania (TiO2). The lanthanum hexaboride hollow cathode design described in this work utilizes both the interior and exterior cathode surfaces, with the additional electrons generated removing the need for a separate neutralizing source. Automatic feedback control of plasma source cathode-to-anode accelerator voltage (AV—via argon gas flow to the anode and/or cathode plasma source areas) and accelerator current (AC—via an external high-current power supply) provides independent control of the ion energy distribution function and ion current density, respectively. Automated run-to-run reproducibility (over six separate deposition runs) in TiO2 refractive index (550 nm) was demonstrated as 2.416 ± 0.008 (spread quoted as one standard deviation), which is well within the required refractive index control for optical coating applications. Variation in refractive index is achievable through control of AV (ion energy) and/or AC (ion current density), directly influencing deposited TiO2 structural phase. Measured dependencies of TiO2 refractive index and extinction coefficient on AV and AC are described. Optimum plasma source parameters for assisted electron beam deposition of TiO2 optical thin-film applications are highlighted. View Full-Text
Keywords: plasma ion source; Titania; refractive index; accelerator current; accelerator voltage plasma ion source; Titania; refractive index; accelerator current; accelerator voltage

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Hui, B.; Fu, X.; Gibson, D.; Child, D.; Song, S.; Fleming, L.; Rutins, G.; Chu, H.O.; Clark, C.; Reid, S. Automated Control of Plasma Ion-Assisted Electron Beam-Deposited TiO2 Optical Thin Films. Coatings 2018, 8, 272.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Coatings EISSN 2079-6412 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top