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91.
Prof. Dr. Theodor Doll Dr. Juan J. Velasco‐Velez Dr. Dirk Rosenthal Dr. Jonathan Avila Prof. Dr. Victor Fuenzalida 《Chemphyschem》2013,14(11):2505-2510
Microchemical sensors and catalytic reactors make use of gases during adsorption in specific ways on selected materials. Fine‐tuning is normally achieved by morphological control and material doping. The latter relates surface properties to the electronic structure of the bulk, and this suggests the possibility of electronic control. Although unusual for catalytic surfaces, such phenomena are sometimes reported for microsensors, but with little understanding of the underlying mechanisms. Herein, direct observation of the electroadsorptive effect by a combination of X‐ray photoelectron spectroscopy and conductivity analysis on nanometre‐thick semiconductor films on buried control electrodes is reported. For the SnO2/NO2 model system, NO3 surface species, which normally decay at the latest within minutes, can be kept stable for 1.5 h with a high coverage of 15 % under appropriate electric fields. This includes uncharged states, too, and implies that nanoelectronic structures provide control over the predominant adsorbate conformation on exterior surfaces and thus opens the field for chemically reactive interfaces with in situ tunability. 相似文献
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Kwong-Kit Choi Carlos Monroy Venkataraman Swaminathan Theodor Tamir Ming Leung John Devitt David Forrai Darrel Endres 《Infrared Physics & Technology》2007,50(2-3):124-135
Previously, we demonstrated a large format 1024 × 1024 corrugated quantum well infrared photodetector focal plane array (C-QWIP FPA). The FPA has a cutoff at 8.6 μm and is BLIP at 76 K with f/1.8 optics. The pixel had a shallow trapezoidal geometry that simplified processing but limited the quantum efficiency QE. In this paper, we will present two approaches to achieve a larger QE for the C-QWIPs. The first approach increases the size of the corrugations for more active volume and adopts a nearly triangular pixel geometry for larger light reflecting surfaces. With these improvements, QE is predicted to be about 35% for a pair of inclined sidewalls, which is more than twice the previous value. The second approach is to use Fabry–Perot resonant oscillations inside the corrugated cavities to enhance the vertical electric field strength. With this approach, a larger QE of 50% can be achieved within certain spectral regions without using either very thick active layers or anti-reflection coatings. The former approach has been adopted to produce two FPAs, and the preliminary experimental results will be discussed. In this paper, we also describe using voltage tunable detector materials to achieve multi-color capability for these FPAs. 相似文献
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Theodor St. Warunis 《Fresenius' Journal of Analytical Chemistry》1912,51(7-8):480-481
Ohne ZusammenfassungMitteilung aus dem Warunis'schen Privatlaboratorium in Athen. 相似文献
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Theodor Heczko 《Fresenius' Journal of Analytical Chemistry》1928,75(5):183-190
Ohne Zusammenfassung 相似文献