• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.360-360
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• 2012

Zn-Sn-O (Zinc-Tin-Oxide; ZTO) thin films have been gaining extensive academic and industrial attentions owing to a semiconducting channel materials applicable to large-sized flat-panel displays. Due to the constituent oxides i.e., ZnO and SnO2, the resultant Zn-Sn-O thin films possess artificially controllable bandgaps and transmittances especially effective in the visible regime. The current approach employed RF sputtering in depositing the Zn-Sn-O thin films onto glass substrates at ambient conditions. This work places its main emphases on the electrical/optical features which are closely related to the combinations of processing variables. The electrical characterizations are performed using dc-based current-voltage characteristics and ac-based impedance spectroscopy. The optical constants, i.e., refractive index and extinction coefficient, are calculated through spectroscopic ellipsometry along with the estimation of bandgaps. The charge transport of the deposited ZTO thin films is based on electrons characteristic of n-type conduction. In addition to the basic electrical/optical information, the delicate manipulation of n-type conduction is indispensible in diversifying the industrial applications of the ZTO thin films as active devices in information and energy products. Ultimately, the electrical properties are correlated to the processing variables along with the underlying mechanism which largely determines the electrical and optical properties.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.705-710
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• 2015

The fabrication process of thin boron-doped nanocrystalline diamond (B-NCD) microelectrodes on fused silica single mode optical fiber cladding has been investigated. The B-NCD films were deposited on the fibers using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) at glass substrate temperature of 475 ℃. We have obtained homogenous, continuous and polycrystalline surface morphology with high sp³ content in B-NCD films and mean grain size in the range of 100-250 nm. The films deposited on the glass reference samples exhibit high refractive index (n=2.05 at λ=550 nm) and low extinction coefficient. Furthermore, cyclic voltammograms (CV) were recorded to determine the electrochemical window and reaction reversibility at the B-NCD fiber-based electrode. CV measurements in aqueous media consisting of 5 mM K₃[Fe(CN)₆] in 0.5 M Na₂SO₄ demonstrated a width of the electrochemical window up to 1.03 V and relatively fast kinetics expressed by a redox peak splitting below 500 mV. Moreover, thanks to high-n B-NCD overlay, the coated fibers can be also used for enhancing the sensitivity of long-period gratings (LPGs) induced in the fiber. The LPG is capable of measuring variations in refractive index of the surrounding liquid by tracing the shift in resonance appearing in the transmitted spectrum. Possible combined CV and LPG-based measurements are discussed in this work.