@article{ishmael_slomski_luo_white_hunt_mandzy_muth_nesbit_paskova_straka_et al._2014, title={Thermal conductivity and dielectric properties of a TiO2-based electrical insulator for use with high temperature superconductor-based magnets}, volume={27}, ISSN={["1361-6668"]}, DOI={10.1088/0953-2048/27/9/095018}, abstractNote={Quench protection is a remaining challenge impeding the implementation of high temperature superconductor (HTS)-based magnet applications. This is due primarily to the slow normal zone propagation velocity (NZPV) observed in Bi2Sr2CaCu2OX (Bi2212) and (RE)Ba2Cu3O7 − x (REBCO) systems. Recent computational and experimental findings reveal significant improvements in turn-to-turn NZPV, resulting in a magnet that is more stable and easier to protect through three-dimensional normal zone growth (Phillips M 2009; Ishmael S et al 2013 IEEE Trans. Appl. Supercond. 23 7201311). These improvements are achieved by replacing conventional insulation materials, such as Kapton and mullite braid, with a thin, thermally conducting, electrically-insulating ceramic oxide coating. This paper reports on the temperature-dependent thermal properties, electrical breakdown limits and microstructural characteristics of a titanium oxide (TiO2) insulation and a doped-TiO2-based proprietary insulation (doped-TiO2) shown previously to enhance quench behavior (Ishmael S et al 2013 IEEE Trans. Appl. Supercond. 23 7201311). Breakdown voltages at 77 K ranging from ∼1.5 kV to over 5 kV are reported. At 4.2 K, the TiO2 increases the thermal conductivity of polyimide by about a factor of 10. With the addition of a dopant, thermal conductivity is increased by an additional 13%, and a high temperature heat treatment increases it by nearly an additional 100%. Similar increases are observed at 77 K and room temperature. These results are understood in the context of the various microstructures observed.}, number={9}, journal={SUPERCONDUCTOR SCIENCE & TECHNOLOGY}, author={Ishmael, S. A. and Slomski, M. and Luo, H. and White, M. and Hunt, A. and Mandzy, N. and Muth, J. F. and Nesbit, R. and Paskova, T. and Straka, W. and et al.}, year={2014}, month={Sep} } @article{luo_wellenius_lunardi_muth_2012, title={Transparent IGZO-Based Logic Gates}, volume={33}, ISSN={["1558-0563"]}, url={http://dx.doi.org/10.1109/led.2012.2186784}, DOI={10.1109/led.2012.2186784}, abstractNote={Optically transparent indium-gallium-zinc-oxide-based nand and nor gates and inverters were fabricated and characterized using transistors deposited at room temperature with 5-, 10-, and 20-μm gate lengths and beta ratio between 2.5 and 40. The nand and nor gates' operation frequencies were measured up to 5 kHz. The individual transistors were measured to have saturation mobility of 14 cm2/V ·s, subthreshold swing of 190 mV/dec, and current on/off ratios in excess of 108. Logic operations were satisfactorily demonstrated for bias voltage between 1 and 20 V. These results indicate that viable digital logic can be applied particularly where optical transparency or the use of novel flexible substrates is more important than the operating speeds.}, number={5}, journal={IEEE ELECTRON DEVICE LETTERS}, author={Luo, Haojun and Wellenius, Patrick and Lunardi, Leda and Muth, John F.}, year={2012}, month={May}, pages={673–675} } @article{suresh_wellenius_baliga_luo_lunardi_muth_2010, title={Fast All-Transparent Integrated Circuits Based on Indium Gallium Zinc Oxide Thin-Film Transistors}, volume={31}, ISSN={["1558-0563"]}, url={http://dx.doi.org/10.1109/led.2010.2041525}, DOI={10.1109/led.2010.2041525}, abstractNote={We describe the fabrication and characterization of visible transparent small-scale indium gallium zinc oxide (IGZO) integrated circuits. The IGZO channel and indium tin oxide (ITO) contacts and interconnects were pulsed laser deposited at room temperature. Low-temperature (200 °C ) atomic-layer-deposited Al2O3 was used as the gate dielectric in bottom-gated thin-film transistors with field-effect mobility near 15 cm2/V·s. Logic inverters and ring oscillators were fabricated and characterized, with operations at frequencies as high as 2.1 MHz, corresponding to a propagation delay of less than 48 ns/stage with a supply voltage of 25 V. To the best of our knowledge, these are the fastest all-transparent oxide semiconductor circuits reported to date.}, number={4}, journal={IEEE ELECTRON DEVICE LETTERS}, author={Suresh, Arun and Wellenius, Patrick and Baliga, Vinay and Luo, Haojun and Lunardi, Leda M. and Muth, John F.}, year={2010}, month={Apr}, pages={317–319} } @article{wellenius_suresh_luo_lunardi_muth_2009, title={An Amorphous Indium-Gallium-Zinc-Oxide Active Matrix Electroluminescent Pixel}, volume={5}, ISSN={["1558-9323"]}, url={http://dx.doi.org/10.1109/jdt.2009.2024012}, DOI={10.1109/JDT.2009.2024012}, abstractNote={In this study, an active matrix pixel was fabricated and characterized using indium gallium zinc oxide (IGZO) thin-film transistors and a novel electroluminescent (EL) Eu:IGZO thin-film phosphor. The results show that even large and unoptimized IGZO devices are capable of modulating at the frequencies necessary for modern display technology. Furthermore, we demonstrate a rare-earth doped amorphous-oxide semiconductor (AOS) EL phosphor that can be modulated via a TFT.}, number={12}, journal={JOURNAL OF DISPLAY TECHNOLOGY}, author={Wellenius, Patrick and Suresh, Arun and Luo, Haojun and Lunardi, Leda M. and Muth, John F.}, year={2009}, month={Dec}, pages={438–445} }