TY - JOUR A1 - Schels, Andreas A1 - Edler, Simon A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Ritter, Daniela A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Meyer, Manuel A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner, Philipp A1 - Schreiner, Rupert T1 - In situ quantitative field emission imaging using a low-cost CMOS imaging sensor JF - Journal of Vacuum Science & Technology B N2 - Spatially resolved field emission measurements represent an important factor in further development of existing field emitter concepts. In this work, we present a novel approach that allows quantitative analysis of individual emission spots from integral current-voltage measurements using a low-cost and commercially available CMOS camera. By combining different exposure times to extrapolate oversaturated and underexposed pixels, a near congruence of integral current and image brightness is shown. The extrapolation also allows parallel investigation of all individual tips participating in the total current with currents ranging from a few nanoampere to one microampere per tip. The sensitivity, which is determined by the integral brightness-to-current ratio, remains unchanged within the measurement accuracy even after ten full measurement cycles. Using a point detection algorithm, the proportional current load of each individual tip of the field emitter array is analyzed and compared at different times during the initial measurement cycle. Together with the extracted I-V curves of single emission spots from the integral measurement, the results indicate the effect of premature burnout of particularly sharp tips during conditioning of the emitter. KW - ARRAYS KW - ELECTRON-EMISSION KW - EMITTERS KW - FakANK Y1 - 2022 U6 - https://doi.org/10.1116/6.0001551 VL - 40 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Edler, Simon A1 - Schels, Andreas A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner Philipp, A1 - Schreiner, Rupert T1 - Origin of the current saturation level of p-doped silicon field emitters JF - Journal of Vacuum Science & Technology B N2 - Using p-type semiconductors for field emitters is one simple way to realize an integrated current limiter to improve the lifetime of the cathode. In this work, the origin of the current saturation of p-type silicon emitters is investigated in detail. Single emitters are electrically characterized and compared to simulation results. With a simulation model considering a high surface generation rate and elevated tip temperature, a good agreement to the measured data is found. This observation is supported further by alteration of the surface experimentally. Electrical measurements after different treatments in hydrofluoric acid as well as heated and subsequent operation at room temperature are well explained by the influence of surface generation. Furthermore, it is shown that the field penetration leads to a small voltage drop and a strong geometry-dependent reduction of the field enhancement factor. KW - EMISSION KW - GROWTH KW - NATIVE-OXIDE Y1 - 2022 U6 - https://doi.org/10.1116/6.0001554 VL - 40 IS - 1 PB - AIP Publishing ER - TY - GEN A1 - Düsberg, Felix A1 - Bachmann, Michael A1 - Edler, Simon A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert A1 - Bunert, Erik A1 - Wendt, Cornelius A1 - Zimmermann, Stefan T1 - Novel Non-Radiative Electron Source T2 - 43rd International Symposium of Capillary Chromatography & 16h GC x GC Symposium 2019 N2 - Recently a non-radioactive electron capture detector based on a thermionic electron emitter has been demonstrated [1]. Using field emitter arrays (FEAs) would yield non-radioactive portable low power devices with fast switching capability. By combining FEAs with a vacuum-sealed housing and an electron transparent membrane window, such electron sources can be operated in an ambient pressure environment. Y1 - 2019 ER - TY - CHAP A1 - Buchner, Philipp A1 - Kaiser, Alexander A1 - Hausladen, Matthias A1 - Bartl, Mathias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Silicon Nanowire Field Emitters with Integrated Extraction Gates Using Benzocyclobutene as an Insulator T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - We are continuously improving the performance of our field emission electron sources. In this work a geometrically optimized design of electron sources with silicon nanowire field emitters on pillars was fabricated. This new design increased the packing density of the emitters by using a hexagonal arrangement of the pillars and a pillar spacing of 40 µm. Benzocyclobutene was used as the insulator material for an integrated (Cr/Ni) extraction gate. A modified fabrication process for the field emitters further improved reproducibility and reliability. An emission current of about 0.4 mA was measured for 30 minutes at an extraction voltage of 250 V and an anode voltage of 500 V. Electron transmission through the gate reached almost 100%. Y1 - 2024 U6 - https://doi.org/10.1109/IVNC63480.2024.10652314 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Hausladen, Matthias A1 - Bomke, Vitali A1 - Buchner, Philipp A1 - Bachmann, Michael A1 - Knapek, Alexandr A1 - Schreiner, Rupert T1 - Influence of Geometrical Arrangements of Si Tip Arrays Fabricated by Laser Micromachining on their Emission Behaviour T2 - 2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France N2 - ensely packed emitters on a field emission array lead typically to mutual shielding. Taking biology as a role model for geometric arrangements could be a way to reduce this effect. For comparison, two electron sources, one with a spiral and a second with conventional rectangular (orthogonal) arranged emitters, were fabricated and investigated. Emission currents of 6 µA in the spiral ordered array and 120 µA in the rectangular array were reached with an extraction voltage of 400 V. From a mid-term measurement over 1 h a current stability of ±8.8 % (spiral) respectively ±5.7 % (rectangular) with a mean degradation of -3.0 µA/h (spiral) and -0.12 µA/h (rectangular) could be observed. KW - aperture field KW - emission grid KW - Fabrication KW - laser micromachining KW - parastichy tip arrangements KW - silicon field emission KW - Stability analysis KW - Spirals KW - Field emitter array KW - Voltage measurement Y1 - 2021 SN - 978-1-6654-2589-6 U6 - https://doi.org/10.1109/IVNC52431.2021.9600717 SN - 2380-6311 PB - IEEE CY - Piscataway, N.J. ER - TY - CHAP A1 - Buchner, Philipp A1 - Bomke, Vitali A1 - Hausladen, Matthias A1 - Edler, Simon A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Investigation on the Emission Behaviour of p-doped Silicon Field Emission Arrays with Individually Controllable Single Tips T2 - 2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France N2 - Four individually controllable emission tips consisting of <111> p-Type silicon, were structured on a glass substrate by laser ablation. A matching extraction grid was manufactured in the same manner and aligned with the emitters. The resulting samples were characterized in ultra-high vacuum. As expected, the individual currents show a strong saturation and in the saturation region a considerably lower current fluctuation than n-type silicon due to charge carrier depletion. The individual tips behave completely independent behaviour from each other and the overall emission can be deduced from the sum of the currents through the individual tips. Y1 - 2021 SN - 978-1-6654-2589-6 U6 - https://doi.org/10.1109/IVNC52431.2021.9600756 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Eiler, Julian A1 - Högl, Christina A1 - Lindner, Matthias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Miniaturized Surface Dielectric Barrier Discharge Plasma Actuators for Application in Chemical Analysis Systems T2 - 2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA N2 - A new concept for a miniaturized planar ion source based on a surface dielectric barrier discharge (SDBD) is presented. A fabrication method based on a stamping process is described, and the plasma actuators are characterized based on their power in dependence of the applied voltage. The voltage for plasma ignition is approx. 1 kV with a maximum plasma power of 40 W/m at 3,4 kV. KW - Actuators KW - Discharges (electric) KW - Ion sources KW - Low Temperature Plasma KW - Plasma KW - Plasma Actuator KW - Plasmas KW - Surface Dielectric Barrier Discharge KW - Surface discharges KW - Vacuum systems KW - Voltage Y1 - 2023 SN - 979-8-3503-0143-4 U6 - https://doi.org/10.1109/IVNC57695.2023.10188884 SP - 40 EP - 42 PB - IEEE ER - TY - CHAP A1 - Bartl, Mathias A1 - Buchner, Philipp A1 - Hausladen, Matthias A1 - Asgharzadehkhorasani, Ali A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Simulations and Investigations of Silicon Nanowire Field Emitters T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - The emission behavior of field emission electron sources consisting of a silicon nanowire cathode, an extraction grid electrode and a planar anode was investigated based on a particle tracing simulation using FEM. The focus was on the influence of the grid geometry as well as the positioning of the grid relative to the emitters on the electron transmission. The highest transmission can be achieved with the emitter tips protruding 10 µm trough the extraction grid openings. The transmission decreases more rapidly with increasing distance between the tip and the grid the thicker the grid is. Y1 - 2024 U6 - https://doi.org/10.1109/IVNC63480.2024.10652355 SP - 1 EP - 2 PB - IEEE ER - TY - JOUR A1 - Hausladen, Matthias A1 - Buchner, Philipp A1 - Bartl, Mathias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Integrated multichip field emission electron source fabricated by laser-micromachining and MEMS technology JF - Journal of Vacuum Science & Technology B N2 - In this work, high-current field emission electron source chips were fabricated using laser-micromachining and MEMS technology. The resulting chips were combined with commercially available printed circuit boards (PCBs) to obtain a multichip electron source. By controlling the separate electron sources using an external current control circuit, we were able to divide the desired total current evenly across the individual chips deployed in the PCB-carrier. In consequence, we were able to show a decreased degradation due to the reduced current load per chip. First, a single electron source chip was measured without current regulation. A steady-state emission current of 1 mA with a high stability of ±1.3% at an extraction voltage of 250 V was observed. At this current level, a mean degradation slope of −0.7 μA/min with a nearly perfect transmission ratio of 99% ± 0.4% was determined. The measurements of a fully assembled multichip PCB-carrier electron source, using a current control circuit for regulation, showed that an even distribution of the desired total current led to a decreased degradation. This was determined by the increase in the required extraction voltage over time. For this purpose, two current levels were applied to the electron source chips of the PCB-carrier using an external current control circuit. First, 300 μA total current was evenly distributed among the individual electron source chips followed by the emission of 300 μA per electron source chip. This allows the observation of the influence of a distributed and nondistributed total current, carried by the electron source chips. Thereby, we obtained an increase in the mean degradation slope from +0.011 V/min (300 μA distributed) to +0.239 V/min (300 μA per chip), which is approximately 21 times higher. Moreover, our current control circuit improved the current stability to under 0.1% for both current levels, 300 μA distributed and 300 μA per chip. KW - MEMS technology KW - Field emitter arrays KW - Electron sources KW - Laser micromachining Y1 - 2024 U6 - https://doi.org/10.1116/6.0003233 VL - 42 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Prommesberger, Christian A1 - Bachmann, Michael A1 - Düsberg, Felix A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Hofmann, Martin A1 - Pahlke, Andreas A1 - Schreiner, Rupert T1 - Regulation of the Transmitted Electron Flux in a Field-Emission Electron Source Demonstrated on Si Nanowhisker Cathodes JF - IEEE Transactions on Electron Devices N2 - We report on a method to stabilize the transmitted electron flux in a field-emission electron source using an external regulation circuit. The electron source was realized with an array of silicon (Si) nanowhiskers on the top of elongated pillar structures, a mica spacer, and an extraction grid made of Si. As for most applications, the emitted electron current from the cathode is not as crucial as the transmitted electron flux through the extraction grid toward the anode. We investigated a method which allows the regulation directly by the emitted electron flux and not merely on the cathode current. By using this method, we were able to stabilize the emitted electron flux of our electron source down to values below 1%. Simultaneously, it was shown that there is the possibility to stabilize the influencing value in the real application as well. The effectiveness of this method was demonstrated successfully with an X-ray source setup. The measured X-ray photon count rate was stabilized to a standard deviation of 0.30% at a pressure of 1 × 10 -7 mbar. Even in harsh environment of 2 × 10 -5 mbar, a stabilization of the X-ray photon count rate down to a value of 0.63% was achieved. KW - Cathodes KW - Nanostructured devices KW - Current measurement KW - Photonics KW - Electron sources KW - Emissions KW - Voltage measurement Y1 - 2017 U6 - https://doi.org/10.1109/TED.2017.2763239 SN - 5128-5133 VL - 64 IS - 12 PB - IEEE ER - TY - JOUR A1 - Langer, Christoph A1 - Bomke, Vitali A1 - Hausladen, Matthias A1 - Ławrowski, Robert Damian A1 - Prommesberger, Christian A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Silicon Chip Field Emission Electron Source Fabricated by Laser Micromachining JF - Journal of Vacuum Science & Technology B N2 - The components for a silicon chip electron source were fabricated by laser micromachining using pulsed laser ablation and wet chemical cleaning and etching dips. The field emission electron source consists of a silicon field emission cathode with 4 × 4 conical shaped emitters with a height of 250 μm and a tip radius of about 50 nm, a 50 μm thick laser-structured mica spacer, and a silicon grid electrode with a grid periodicity of 200 μm and a bar width of 50 μm. These three components are combined to a single chip with the size of 14 × 10 mm2 and the thickness of 1 mm to form the electron source. Several of these devices were characterized in ultrahigh vacuum. Onset voltages of about 165 V and cathode currents of about 15 μA for voltages lower than 350 V were observed. Operating the electron source with an anode voltage of 500 V and an extraction grid voltage of 300 V yielded a cathode current of 4.5 μA ± 8.9%, an anode current of 4.0 μA ± 9.6%, and a corresponding grid transmittance of 89%. Regulating the anode current by the extraction grid voltage, an extremely stable anode current of 5.0 μA ± 0.017% was observed. A long-term measurement over 120 h was performed, and no significant degradation or failure was observed. KW - Ultra-high vacuum KW - Field emitter arrays KW - Etching KW - Electrical properties and parameters KW - Electron sources KW - Laser ablation KW - Laser micromachining KW - Silicon chip KW - Triodes Y1 - 2020 U6 - https://doi.org/10.1116/1.5134872 VL - 38 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Breuer, Janis A1 - Bachmann, Michael A1 - Düsberg, Felix A1 - Pahlke, Andreas A1 - Edler, Simon A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert A1 - Serbun, Pavel A1 - Lützenkirchen-Hecht, Dirk T1 - Extraction of the current distribution out of saturated integral measurement data of p-type silicon field emitter arrays JF - Journal of Vacuum Science and Technology B N2 - At the moment, only complicated techniques are known for the determination of array properties of field emitter arrays such as the number of active tips, the current distribution, or the individual tip radii. In this work, a method for extracting these parameters from integral measurement data is presented. A model describing the characteristics of a single emitter, including the saturation as a function of the applied voltage and the emitter radius, is developed. It is shown that experimental data of field emitter arrays can be represented as the sum of these functions and the characteristic parameters can be fitted to field emission data of an array. Using this method, the values of the radii as well as the parameters of distribution models can be determined directly. Analysis of experimental data from p-type Si emitter arrays shows that only 1–2% of the tips contribute significantly. Y1 - 2018 U6 - https://doi.org/10.1116/1.5035189 VL - 36 IS - 5 PB - AIP Publishing ER - TY - JOUR A1 - Edler, Simon A1 - Bachmann, Michael A1 - Breuer, Janis A1 - Dams, Florian A1 - Düsberg, Felix A1 - Hofmann, Martin A1 - Jakšič, Jasna A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup JF - Journal of Applied Physics N2 - In the present work, black-silicon field emitter arrays (FEAs) are investigated regarding the influence of residual gas pressure on the characteristics and lifetime in the high voltage triode setup. Current-voltage-characteristics at different pressure levels are recorded and show a decreasing emission current with rising pressure. This decrease can be explained by an increase of the work function and charging of the emitter surface caused by adsorbates. The emission current can be restored to its initial value by heating of the FEA up to 110 °C during active emission. With this regeneration procedure, an extended lifetime from about 20 h to 440 h at a residual gas pressure of 10−5 mbar is achieved. Y1 - 2017 U6 - https://doi.org/10.1063/1.4987134 VL - 122 ER -