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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission current investigation of p-type and metallized silicon emitters in the frequency domain
摘要： We investigated two different field emitter arrays consisting of 10×10 p-type and 10×10 undoped Au-coated high aspect ratio silicon tips. The I-V characterization of the p-type sample showed a pronounced saturation for voltages higher than 500 V and a maximum emission current of 39 nA. The metallized sample revealed a FN-like emission up to several μA. The metallized and the p-type sample operating below the saturation region showed high current fluctuations of ±16%. Whereas, the metallized sample with current regulation and the p-type sample in the saturation yielded a current stability of ±0.4% and ±0.3%, respectively. Investigations in the frequency domain revealed the for field emission typical 1/f-noise. By operating in the saturation region (p-type sample) or using an emission current regulation (metallized sample) the noise level was reduced by at least 20 dB. Finally, the p-type sample was illuminated by a light emitting diode to increase and modulate the emission current in the saturation region. The emission current was increased by a factor of 3.7 to 145 nA. With this configuration we emulated an unstable emission behavior and evaluated the performance of our emission current regulation circuit.
关键词： field emitter array,current stability,current fluctuation,field emission noise,field emission,silicon tip
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Fluctuations of the emission characteristics of multi-tip field cathodes
摘要： Report presents a complex experimental study of the fluctuations in the emission characteristics of multi-tip field cathodes based on composites "disordered carbon nanotubes in a polymer matrix". The objects of the study: correlation of the glow patterns of the field emission projector with the level of the macroscopic emission current, emission sites activity, distribution of the current load on the emission sites, field enhancement factor of the individual emission sites, dependence of the current-voltage characteristics and effective emission parameters on the voltage and vacuum levels, formation of a calibration grid on the SK-diagram, modeling of the adsorption/desorption processes on the emitter surface.
关键词： emitter surface analysis,field emission images,current fluctuation,nanocomposite,field emission,carbon nanotubes,IVC
更新于2025-09-23 15:21:21
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Origination of Anomalous Current Fluctuation in Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) have been rapidly crowded into the emerging photovoltaics, exhibiting soaring efficiencies over 25%. There are unusual characteristics that have emerged in the progression of these solar cells, such as anomalous current hysteresis and light soaking effect. Here, we first identify a current fluctuation phenomenon in PSCs and show the feature of current fluctuation. Scan derived power conversion efficiency is seriously interrupted by the current fluctuation under working conditions. The hole transport material (HTM) 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD) in PSCs undergoes severe morphological deformation along with the storage time, which results in this current fluctuation phenomenon. Li-bis(trifluoromethanesulfonyl)-imide (LiTFSI) and 4-tert-butylpyridine (tBP) as additives within the spiro-OMeTAD layer induce large pinholes across the whole HTM after the tBP additive escaped and the LiTFSI additive aggregated. These aggregated free Li+ ions would form the ionic conductivity path, replacing the original spiro-OMeTAD HTM layer. The disabled spiro-OMeTAD layer leads to the shorts between Ag electrode and perovskite, causing the anomalous current fluctuation especially under a high scan voltage. Our investigation provides the understanding and how to eliminate the current fluctuation in PSCs, which is essential for further progress in device stability.
关键词： spiro-OMeTAD,perovskite solar cells,hole transport material,stability,current fluctuation
更新于2025-09-12 10:27:22