@article{kiesel_peters_hassan_kowalsky_2009, title={Calibration of a single-mode polymer optical fiber large-strain sensor}, volume={20}, ISSN={["1361-6501"]}, DOI={10.1088/0957-0233/20/3/034016}, abstractNote={We calibrate the phase shift as a function of applied displacement in a polymethylmethacrylate (PMMA) single-mode optical fiber interferometer, operating at a wavelength of 632.8 nm. The phase sensitivity is measured up to 15.8% nominal strain in the fiber. The measured phase–displacement response is compared to a previous analytical formulation for the large deformation response of the polymer optical fiber strain sensor. The formulation includes both the finite deformation of the optical fiber and nonlinear strain-optic effects at large deformations. Using previously measured values for the linear and nonlinear mechanical response of the fiber, the nonlinear strain-optic effects are calibrated from the current experimental data. This calibration demonstrates that the nonlinearities in the strain-optic effect are of the same order of magnitude as those in the mechanical response of the PMMA optical fiber sensor.}, number={3}, journal={MEASUREMENT SCIENCE AND TECHNOLOGY}, author={Kiesel, Sharon and Peters, Kara and Hassan, Tasnim and Kowalsky, Mervyn}, year={2009}, month={Mar} }
 @article{kiesel_peters_hassan_kowalsky_2008, title={Large deformation in-fiber polymer optical fiber sensor}, volume={20}, ISSN={["1941-0174"]}, DOI={10.1109/LPT.2008.916929}, abstractNote={We demonstrate the measurement of the phase shift in a polymethylmethacrylate single-mode optical fiber interferometer, operating at a wavelength of 632.8 nm, up to 15.8% nominal strain in the fiber. The phase-displacement sensitivity is measured to be 1.39 x10 radldrm-1 for this strain range. This strain range is well beyond the yield strain of the polymer fiber and that previously measured for polymer Bragg gratings and silica optical fiber sensors.}, number={5-8}, journal={IEEE PHOTONICS TECHNOLOGY LETTERS}, author={Kiesel, Sharon and Peters, Kara and Hassan, Tasnim and Kowalsky, Mervyn}, year={2008}, pages={416–418} }
 @article{burnette_kiesel_sayers_nemanich_2008, title={Titanium Interlayer Mediated Epitaxy of CoSi2 on Si1-xGex}, volume={516}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2007.08.045}, abstractNote={Abstract Titanium Interlayer Mediated Epitaxy (TIME) has been shown to promote the formation of epitaxial CoSi2 on Si (100). Similarities between Si and Si1−xGex alloys have motivated a study of whether the TIME process could be successful in forming epitaxial CoSi2 on Si1−xGex. Titanium layers of varying thickness were deposited as interlayers between a Co layer and c-Si/Si0.8Ge0.2 grown epitaxially onto Si (100) to investigate their role in the formation of epitaxial CoSi2 on Si1−xGex alloys. The effect of Ti interlayer thickness on the orientation of CoSi2 to the Si1−xGex substrate, and the conditions under which a polycrystalline CoSi2 film has been formed have been studied. It was found that Ti was beneficial in promoting epitaxy to the substrate in all cases. The experimental results indicate that with a Ti interlayer thickness of ∼ 50 A, the formation of epitaxial CoSi2 adjacent to the substrate was achieved, and pinhole formation was minimized. It was also observed that for increased interlayer thickness, Ti reacted with Si to form a titanium silicide.}, number={8}, journal={THIN SOLID FILMS}, author={Burnette, James E. and Kiesel, Sharon and Sayers, Dale E. and Nemanich, Robert J.}, year={2008}, month={Feb}, pages={1809–1817} }
 @article{kiesel_peters_hassan_kowalsky_2007, title={Behaviour of intrinsic polymer optical fibre sensor for large-strain applications}, volume={18}, ISSN={["1361-6501"]}, DOI={10.1088/0957-0233/18/10/S16}, abstractNote={This paper derives the phase response of a single-mode polymer optical fibre for large-strain applications. The role of the finite deformation of the optical fibre and nonlinear strain optic effects are derived using a second order strain assumption and shown to be important at strain magnitudes as small as 1%. In addition, the role of the core radius change on the propagation constant is derived, but it is shown to be negligible as compared to the previous effects. It is shown that four mechanical and six opto-mechanical parameters must be calibrated to apply the sensor under arbitrary axial and transverse loading. The mechanical nonlinearity of a typical single-mode polymer optical fibre is experimentally measured in axial tension and is shown to be more significant than that of their silica counterpart. The mechanical parameters of the single-mode polymer optical fibre are also measured for a variety of strain rates, from which it is demonstrated that the strain rate has a strong influence on yield stress and strain. The calibrated constants themselves are less affected by strain rate.}, number={10}, journal={MEASUREMENT SCIENCE AND TECHNOLOGY}, author={Kiesel, Sharon and Peters, Kara and Hassan, Tasnim and Kowalsky, Mervyn}, year={2007}, month={Oct}, pages={3144–3154} }
 @article{coppa_fulton_kiesel_davis_pandarinath_burnette_nemanich_smith_2005, title={Structural, microstructural, and electrical properties of gold films and Schottky contacts on remote plasma-cleaned, n-type ZnO{0001} surfaces}, volume={97}, ISSN={["1089-7550"]}, DOI={10.1063/1.1898436}, abstractNote={Current–voltage measurements of Au contacts deposited on ex situ cleaned, n-type ZnO(0001) [(0001¯)] surfaces showed reverse bias leakage current densities of ∼0.01(∼0.1)A∕cm2 at 4.6 (3.75) V reverse bias and ideality factors >2 (both surfaces) before sharp, permanent breakdown (soft breakdown). This behavior was due primarily to the presence of (1.6–2.0)±0.1[(0.7–2.6)±0.1] monolayers (ML) of hydroxide, which forms an electron accumulation layer and increases the surface conductivity. In situ remote plasma cleaning of the (0001) [(0001¯)] surfaces using a 20vol%O2∕80vol%He mixture for the optimized temperatures, times, and pressure of 550±20°C(525±20°C), 60 (30) min, and 0.050 Torr reduced the thickness of the hydroxide layer to ∼0.4±0.1ML and completely eliminated all detectable hydrocarbon contamination. Subsequent cooling of both surfaces in the plasma ambient resulted in the chemisorption of oxygen and a change from 0.2 eV of downward band bending for samples cooled in vacuum to 0.3 eV of upward band bending indicative of the formation of a depletion layer of lower surface conductivity. Cooling in either ambient produced stoichiometric ZnO{0001} surfaces having an ordered crystallography as well as a step-and-terrace microstructure on the (0001¯) surface; the (0001) surface was without distinctive features. Sequentially deposited, unpatterned Au films, and presumably the rectifying gold contacts, initially grew on both surfaces cooled in the plasma ambient via the formation of islands that subsequently coalesced, as indicated by calculations from x-ray photoelectron spectroscopy data and confirmed by transmission electron microscopy. Calculations from the current–voltage data of the best contacts revealed barrier heights on the (0001) [(0001¯)] surfaces of 0.71±0.05(0.60±0.05)eV, a saturation current density of (4±0.5)×10−6A∕cm2(2.0±0.5×10−4A∕cm2), a lower value of n=1.17±0.05(1.03±0.05), a significantly lower leakage current density of ∼1.0×10−4A∕cm2(∼91×10−9A∕cm2) at 8.5 (7.0) V reverse bias prior to sharp, permanent breakdown (soft breakdown). All measured barrier heights were lower than the predicted Schottky–Mott value of 1.0 eV, indicating that the interface structure and the associated interface states affect the Schottky barrier. However, the constancy in the full width at half maximum of the core levels for Zn 2p(1.9±0.1eV) and O 1s(1.5±0.1eV), before and after sequential in situ Au depositions, indicated an abrupt, unreacted Au∕ZnO(0001) interface. Transmission electron microscopy confirmed the abruptness of an epitaxial interface. Annealing the contacts on the (0001) surface to 80±5 and 150±5°C resulted in decreases in the ideality factors to 1.12±0.05 and 1.09±0.05 and increases in saturation current density to 9.05 and 4.34μA∕cm2, the barrier height to 0.82±0.5 and 0.79±0.5eV, and in the leakage current densities to ∼2×10−3A∕cm2 at 6 V and ∼20×10−3A∕cm2 at 7 V, respectively.}, number={10}, journal={JOURNAL OF APPLIED PHYSICS}, author={Coppa, BJ and Fulton, CC and Kiesel, SM and Davis, RF and Pandarinath, C and Burnette, JE and Nemanich, RJ and Smith, DJ}, year={2005}, month={May} }