TY - JOUR A1 - Dams, Florian A1 - Schreiner, Rupert T1 - Influencing factors on the sensitivity of MEMS-based thermal conductivity vacuum gauges JF - Journal of vacuum science & technology A N2 - The measurement range of thermal conductivity vacuum gauges is mainly influenced by the sensitivity of the sensing element to variations in pressure. An enhanced definition of sensitivity shows its theoretical dependence on the geometric measures of the sensor element at the whole pressure range. This value gives the possibility of direct comparison between different types of sensor structures without the influence of the operating conditions. To study the influencing factors, sensor chips with heated surfaces in the order of some tens of mm 2 were realized by microelectromechanical systems-based fabrication techniques. By a silicon-glass hybrid process two cold planes were formed in a distance of 150 mu m above and below the heated element. The thermal conductance of devices with different geometric measures was determined in constant temperature operating mode by usage of embedded measurement equipment. In this configuration the sensor signals were sensitive to pressure in a region from 10(-5) mbar. The sensitivity was extracted by a fit of the theoretical model to the measurement data and showed the predicted dependencies on the geometric measures. (C) 2014 American Vacuum Society. KW - Pirani Gauge KW - Pressure Sensor Y1 - 2014 U6 - https://doi.org/10.1116/1.4867486 VL - 32 IS - 3 PB - AVS ER - TY - JOUR A1 - Dams, Florian A1 - Navitski, Aliaksandr A1 - Prommesberger, Christian A1 - Serbun, Pavel A1 - Langer, Christoph A1 - Müller, Günter A1 - Schreiner, Rupert T1 - Homogeneous Field Emission Cathodes With Precisely Adjustable Geometry Fabricated by Silicon Technology JF - IEEE Transactions on Electron Devices N2 - Silicon-based cathodes with precisely aligned field emitter arrays of sharp tips applicable for miniaturized electron sources were successfully fabricated and characterized. This was made possible by an improved fabrication process using wet thermal oxidation, wet etching, and reactive-ion etching steps with adjustable anisotropy. As substrate materials, both p-doped silicon and n-doped silicon were used. The cathode chips contain about 3 × 10 5 Si tips/cm 2 in a triangular array with tip heights of 2.5 μm, tip radii of less than 30 nm, and spacing of 20 μm. Well-aligned field emission (FE) and excellent homogeneity from all tips (i.e., 100% efficiency) and maximum stable currents of typically 0.1 μA (0.6 μA) for p (n)-type Si were reproducibly achieved. The current-voltage characteristics of the p-Si tips exhibit the expected saturation at around 10 nA with around ten times better current stability, whereas the n-Si tips show the usual Fowler-Nordheim behavior. Additional coating of the Si tips with 5-nm Cr and 10-nm Au layers resulted in improved stability and at least five times higher average FE current limits (about 3 μA) at about 30% higher operation voltage. KW - cathodes KW - electron field emission KW - elemental semiconductors KW - Field emission (FE) cathodes KW - field emitter array (FEA) KW - miniaturized electron sources KW - oxidation KW - silicon KW - silicon tips KW - sputter etching Y1 - 2012 U6 - https://doi.org/10.1109/TED.2012.2206598 SN - 0018-9383 SN - 1557-9646 VL - 59 IS - 10 SP - 2832 EP - 2837 PB - IEEE ER - TY - JOUR A1 - Tan, Pi Lin A1 - Yeap, Guan Yeow A1 - Chow, Wen Shyang A1 - Schreiner, Rupert A1 - Cheong, Kuan Yew T1 - Effect of Thickness of Porphyrin on Electrical Properties of Organic Devices JF - Advanced Materials Research (AMR) N2 - The study on electrical properties for both 2,3,7,8,12,13,17,18-octaethyl-21,23H-porphine Cu (II) (Cu-porphyrin) and 2,3,7,8,12,13,17,18-octaethyl-21,23H-porphine (porphyrin) thin film, which were fabricated using spin coating method was conducted. Porphyrins were diluted with chloroform of various concentrations (0.05 mg/ml, 0.1 mg/ml, 0.5 mg/ml, 2.0 mg/ml and 3.0 mg/ml). The solution was spin coated on top of glass substrates. A layer of aluminum was evaporated on top of the organic thin film through thermal evaporation and shadow mask was placed on top of the organic thin film where two electrodes with a gap of 50 μm were formed. Surface morphology of the organic thin film was observed by scanning electron microscope (SEM) and profilometer. Different concentrations of organic solutions greatly affected the molecular packing and arrangement order of the organic thin film and thickness of the organic layer and eventually affected electrical properties of the devices. KW - Porphyrin KW - Electrical Properties KW - Spin Coating Y1 - 2014 U6 - https://doi.org/10.4028/www.scientific.net/AMR.1024.381 SN - 1662-8985 SN - 1022-6680 VL - 1024 SP - 381 EP - 384 PB - Trans Tech Publications Ltd. CY - Baech ER - TY - JOUR A1 - Langer, Christoph A1 - Berndt, Dominik A1 - Schreiner, Rupert T1 - Sensitivity of thermal conductivity vacuum gauges for constant current and constant temperature operation JF - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics N2 - To optimize the measurement range of thermal conductivity vacuum gauges, an expression for the sensitivity is required that takes into account all geometrical, material-specific, and operating parameters. Therefore, equations of the sensor output signal as a function of the pressure for the constant current and the constant temperature mode have been developed analytically. Based on these equations, the sensitivity of the vacuum gauge and its influencing parameters was investigated and discussed. For comparable conditions, the constant temperature operation shows a significantly higher sensitivity for high pressures, while the constant current operation shows higher sensitivity at low pressures. The sensitivity in both the constant current and the constant temperature mode depends on the ratio of the filament surface area and the parasitic thermal conductance. In addition, for the constant current operation, the sensitivity also depends on the current value and the temperature coefficient of the filament resistor. For the constant temperature operation, the sensitivity additionally depends on the distance of the filament and the reference plane. However, to extend the measurement range of a thermal conductivity vacuum gauge toward low pressures, a reduction of the parasitic thermal conductance is mandatory for both the constant current and the constant temperature mode. Y1 - 2022 U6 - https://doi.org/10.1116/6.0001964 VL - 40 IS - 5 PB - AIP Publishing ER - TY - CHAP A1 - Dams, Florian A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Fabrication process of silicon-tip-arrays for field emission applications T2 - 24th International Vacuum Nanoelectronics Conference (IVNC), 2011 : 18 - 22 July 2011, Historische Stadthalle Wuppertal, Germany N2 - A micromachined process to assemble homogeneous and reproducible tip arrays for field emission applications is developed and characterized. As substrate material p- as well as n-doped silicon is used. Lateral position of the tips is defined by structuring silicon dioxide to discs in a photolithographic process. Vertical structure of the tips is defined by a combination of RIE dry etching with controlled anisotropy and thermally oxidization of silicon in order to sharpen the tips. Hence field emitter arrays (FEAs) can be assembled both as bare and coated cathodes. To assemble field emission diodes, this fabrication process allows placing a metal anode in a micrometer order distance to the tips by a self-aligning procedure. The anode is placed in an evaporation process whereupon sharpening oxide is used as isolator between anode and cathode. Electrical characterization of the cathodes showed very good homogeneity, well alignment and stability over time of emission current from all tips (i.e. 100% efficiency). KW - elemental semiconductors KW - etching KW - fabrication KW - field emission KW - field emitter arrays KW - homogeneity KW - micromachining KW - oxidation, silicon KW - silicon technology Y1 - 2011 UR - https://ieeexplore.ieee.org/document/6004556?arnumber=6004556 SN - 978-3-00-035081-8 SN - 978-1-4577-1243-2 SN - 2380-6311 SN - 2164-2370 SP - 49 EP - 50 PB - IEEE ER - TY - CHAP A1 - Schreiner, Rupert A1 - Mulot, M. A1 - Wiedmann, Jörg A1 - Coenning, W. A1 - Porsche, J. A1 - Gentner, Jean-Louis A1 - Berroth, Manfred A1 - Scholz, Ferdinand A1 - Schwizer, H. T1 - Dynamic measurements on narrow linewidth complex coupled 1.55 μm DFB lasers with gain and index grating in antiphase T2 - Conference Proceedings. Eleventh International Conference on Indium Phosphide and Related Materials (IPRM'99), 16-20 May 1999, Davos, Switzerland N2 - We report on dynamic measurements on antiphase complex coupled 1.55 /spl mu/m DFB lasers. The antiphase complex coupling mechanism is realized by periodically etching the active layer and quarternary InGaAsP overgrowth. This new fabrication approach results in very narrow linewidths measured on devices with rather short resonator lengths. The minimum linewidth for a 375 /spl mu/m long ridge waveguide laser was only 250 kHz at an optical output power of 4 mW. The RC-limited 3dB-bandwidth for those devices was /spl sim/6 GHz. Using circuit model corrections, the intrinsic bandwidth limitation of those lasers was found to be 17.4 GHz. KW - Waveguide lasers KW - Optical resonators KW - Optical waveguides KW - Laser modes KW - Optical coupling KW - Etching KW - Optical device fabrication KW - Length measurement KW - Power lasers KW - Power generation Y1 - 1999 SN - 0-7803-5562-8 U6 - https://doi.org/10.1109/ICIPRM.1999.773626 SP - 25 EP - 28 PB - IEEE CY - Piscataway ER - TY - CHAP A1 - Schreiner, Rupert A1 - Naegele, Peter A1 - Koerbl, Michael A1 - Groening, Albert A1 - Gentner, Jean-Louis A1 - Schweizer, Heinz C. ED - Mirin, Richard P. ED - Menoni, Carmen S. T1 - Monolithically integrated tunable laterally-coupled distributed feedback lasers with self-aligned Ti/Pt/Au ohmic contacts T2 - Proceedings Volume 4871, Semiconductor Lasers and Optical Amplifiers for Lightwave Communication SystemsSemiconductor Lasers and Optical Amplifiers for Lightwave Communication Systems N2 - We present a new method for fabrication of tunable InGaAsP-InP single mode lasers without epitaxial overgrowth. These devices show the advantage of a considerably simplified fabrication process compared to conventional tunable laser types. The lasers comprise an active Bragg reflector integrated with an uncorrugated separately pumped gain region. To overcome the extensive and expensive overgrowth step we realized a surface grating on both sides of the ridge mesa, which provides DFB operation. By adjusting the current through the Bragg reflector, the wavelength can be tuned between 1590.8 nm and 1595.2 nm. A maximum of 11 wavelength channels with an average spacing of ~0.5 nm and a constant optical output power of ~0.5 mW are addressable. Y1 - 2002 U6 - https://doi.org/10.1117/12.457281 PB - SPIE ER - TY - JOUR A1 - Cheong, Kuan Yew A1 - Aw, Kean A1 - Karimov, Khasan S. A1 - Zhao, Feng A1 - Mahroof-Tahir, Mohammad A1 - Schreiner, Rupert T1 - Advances in Smart Materials and Applications JF - Advances in Materials Science and Engineering N2 - This is one of a series of special issues published in Advances in Materials Science and Engineering, focusing on the latest advances of smart materials and their applications. Evolution of engineering materials is strongly depending on the growing transformation of complexity in engineering products. New materials being designed are required to provide specific properties and demonstrate certain functional characteristics by manipulating their dimension, chemistry, and structure through various advanced technologies. Therefore, “smartness” of a material has become the topic of interest. Properties of smart materials may change accordingly to the applied external stimuli. Under the direction of the editorial team, we showcase advances of organic and inorganic based smart materials and their applications in areas of specific interest such as energy, environment, and health. A total of 9 articles are published in this special issue. Six articles are focused on production, synthesis, and optimization of smart materials; and the remaining are dedicated to application of smart materials. Y1 - 2014 U6 - https://doi.org/10.1155/2014/517342 PB - Hindawi ER - TY - CHAP A1 - Saravanan, Brem Kumar A1 - Gerlach, Philipp A1 - Peschke, Martin A1 - Knoedl, Thomas A1 - Schreiner, Rupert A1 - Hanke, Christian A1 - Stegmueller, Bernhard T1 - Integrated DFB laser electro-absorption modulator based on identical MQW-double stack active layer for high-speed modulation beyond 10 GBIT/S T2 - 16th IPRM. 2004 International Conference on Indium Phosphide and Related Materials, 31 May - 04 June 2004, Kagoshima, Japan N2 - Integrated DFBLD-EAM-SOA devices utilizing an identical MQW active region have been realized in the AlGaInAs/InP material system. A fiber-coupled optical power of >6 mW with a 10 dB static extinction, 44 dB SMSR single-mode spectrum and a 3 dBe cutoff frequency of 25 GHz was measured. KW - Quantum well devices KW - Fiber lasers KW - Indium phosphide KW - Optical materials KW - Optical fiber devices KW - High speed optical techniques KW - Optical modulation KW - Cutoff frequency KW - Power measurement KW - Frequency measurement Y1 - 2004 SN - 0-7803-8595-0 U6 - https://doi.org/10.1109/ICIPRM.2004.1442656 SP - 236 EP - 238 PB - IEEE ER - TY - JOUR A1 - Zahner, Th A1 - Schreiner, Rupert A1 - Stierstorfer, R. A1 - Kus, O. A1 - Li, S. T. A1 - Roessler, R. A1 - Pedarnig, J. D. A1 - Bäuerle, D. A1 - Lengfellner, H. T1 - Off-diagonal Seebeck effect and anisotropic thermopower in Bi2Sr2CaCu2O8 thin films JF - Europhysics Letters N2 - The anisotropy ΔS of the thermopower in thin films of the high-Tc superconductor Bi2Sr2CaCu2O8 is investigated using off–c-axis epitaxial film growth and the off-diagonal Seebeck effect. The measurements represent a new method for the investigation of anisotropic transport properties in solids, taking advantage of the availability of oriented grown crystalline thin films instead of using bulk crystals. First results for the temperature dependence ΔS(T) in Bi2Sr2CaCu2O8 thin films are presented and described within a two-band model. Subjecting the films to heat treatments in different gases at relatively low temperatures, ΔS could reversibly be changed in a wide range. Y1 - 1997 U6 - https://doi.org/10.1209/epl/i1997-00521-4 VL - 40 IS - 6 SP - 673 EP - 678 PB - IOP Sciences ER - TY - CHAP A1 - Knodl, Thomas A1 - Hanke, Christian A1 - Saravanan, Brem Kumar A1 - Peschke, Martin A1 - Schreiner, Rupert A1 - Stegmuller, Bernhard ED - Righini, Giancarlo C. ED - Honkanen, Seppo T1 - Integrated 1.3-μm InGaAlAs-InP laser-modulator with double-stack MQW layer structure T2 - Proceedings Volume 5451, Integrated Optics and Photonic Integrated Circuits N2 - We present first experimental results of the successful transfer of our monolithic integrated double-stack multi quantum well laser-modulator approach from the traditional InGaAsP/InP to the more promising InGaAlAs/InP material system. In continuous wave operation at room temperature, the devices achieved threshold currents of <21 mA, fiber coupled optical power levels up to 570 μW and static extinction ratios in the range of 15 dB/V. The measured small-signal modulation bandwidth of about 10 GHz is capacitance limited due to a conservative device layout. Y1 - 2004 U6 - https://doi.org/10.1117/12.544610 PB - SPIE ER - TY - CHAP A1 - Schreiner, Rupert A1 - Grabeldinger, H. A1 - Wiedmann, J. A1 - Wunstel, K. A1 - Porsche, J. A1 - Scholz, Ferdinand A1 - Schweizer, H. T1 - Complex coupled 1.55 mu m tunable super-grating DFB lasers and photonic filters T2 - Compound semiconductors 1999 : proceedings of the Twenty-Sixth International Symposium on Compound Semiconductors held in Berlin, Germany, 22 - 26 August 1999 N2 - We report on the investigation and realization of photonic filters based on the combination of fractional compositions of a few basic grating periods. Using a minimum set of two basic periods Lambda(1) and Lambda(2) we demonstrate comb-like few mode photonic band gap structures with arbitrary numbers of bands and frequency spacing between the bands. Optically integrated filters of different comb periods result in switchable wavelength filters for channel selection in WDM applications. Y1 - 2000 UR - https://www.researchgate.net/publication/296464112_Complex_coupled_155_mu_m_tunable_super-grating_DFB_lasers_and_photonic_filters SN - 0-7503-0704-8 PB - Inst. of Physics Publ. CY - Bristol [u.a.] ER - TY - CHAP A1 - Schreiner, Rupert A1 - Schweizer, Heinz C. T1 - High frequency operation of 1.57 μm laterally gain coupled DFB lasers with self aligned ohmic contacts and nickel surface gratings T2 - IEEE 18th International Semiconductor Laser Conference; 29 Sept.-3 Oct. 2002, Garmisch, Germany N2 - Laterally coupled DFB lasers with self-aligned ohmic contacts show the advantage of a, considerably simplified fabrication process. Side-mode-suppresion-ratios up to 55 dB and 3 dB-bandwidths beyond 15 GHz were obtained for these devices. KW - Frequency KW - Optical coupling KW - Distributed feedback devices KW - Etching KW - Laser theory KW - Laser modes KW - Nickel KW - Laser feedback KW - Waveguide lasers KW - Laser noise Y1 - 2002 SN - 0-7803-7598-X U6 - https://doi.org/10.1109/ISLC.2002.1041099 SP - 21 EP - 22 PB - IEEE ER - TY - CHAP A1 - Podstránský, Jáchym A1 - Hausladen, Matthias A1 - Zlámal, Jakub A1 - Knápek, Alexandr A1 - Schreiner, Rupert T1 - Single Column Multiple Electron Beam Imaging from N-Type Silicon T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - This work is aimed at measuring the electron emission from multiple cathodes formed by n-doped silicon and imaging the electron beams focused by an einzel lens on a CMOS camera. The experimental results are compared with computer simulation to understand the electron emission from the semiconductor cathode and the observed imaging imperfections. Finally, modifications to the experimental setup are suggested that should lead to improvement in the extraction current and spot size of focused electron beams and also better understanding of the processes taking place in the experiment. Y1 - 2024 SN - 979-8-3503-7976-1 U6 - https://doi.org/10.1109/IVNC63480.2024.10652470 SP - 1 EP - 2 PB - IEEE ER -