@inproceedings{PrommesbergerLangerŁawrowskietal., author = {Prommesberger, Christian and Langer, Christoph and Ławrowski, Robert Damian and Muller, F. and Dams, Florian and Schreiner, Rupert and Serbun, Pavel and M{\"u}ller, G{\"u}nter}, title = {Comparison of integral and local field-emission properties of Mo-coated p-Si tip arrays}, series = {2015 28th International Vacuum Nanoelectronics Conference (IVNC), 13-17 July 2015, Guangzhou, China}, booktitle = {2015 28th International Vacuum Nanoelectronics Conference (IVNC), 13-17 July 2015, Guangzhou, China}, publisher = {IEEE}, doi = {10.1109/IVNC.2015.7225579}, pages = {192 -- 193}, abstract = {Silicon tip arrays were fabricated by means of reactive ion etching followed by oxidation for final sharpening and molybdenum thin film coating. The field-emission (FE) properties of these Mo-coated p-Si tip arrays were systemically investigated by different measurement techniques. Integral measurements in diode configuration yielded a turn-on field (for 1 nA) of 22 V/μm and nearly stable FE currents up to 6.6 μA at 38 V/μm. The effective field enhancements factor extracted from the FN plots is about 180. Detailed investigations of these FE arrays were also performed by means of field emission scanning microscopy combined with electron microscopy. A rather limited efficiency of the tips (50\% at 1500 V) and FE homogeneity (180 nA at 700 V) might be correlated with the varying morphology of the tips and the presence of oxides. Local I-V measurements of selected single tips revealed both activation and deactivation effects, which finally resulted in nearly reproducible I-V curves. Current stability measurements at a constant voltage showed rather large fluctuations (0.1-1 μA) of the FE current, which could be reduced up to 1.7\% by using of a PID-regulated voltage source. SEM images showed unchanged tip shape after the current processing.}, language = {en} } @inproceedings{KleshchSerbunOrekhovetal., author = {Kleshch, Victor I. and Serbun, Pavel and Orekhov, Anton and L{\"u}tzenkirchen-Hecht, Dirk and Obraztsov, Alexander N. and Prommesberger, Christian and Langer, Christoph and Schreiner, Rupert and Lutzenkirchen-Hecht, Dirk}, title = {Field emission properties of p-type silicon tips decorated with tungsten nanoparticles}, series = {2017 30th International Vacuum Nanoelectronics Conference (IVNC), 10-14 July 2017, Regensburg, Germany}, booktitle = {2017 30th International Vacuum Nanoelectronics Conference (IVNC), 10-14 July 2017, Regensburg, Germany}, publisher = {IEEE}, doi = {10.1109/IVNC.2017.8051580}, pages = {138 -- 139}, abstract = {An array of conical-shaped p-type silicon tips was fabricated by using reactive ion etching and sharpening oxidation. The apex of each tip was decorated by a tungsten hemispherical nanoparticle. Field emission properties of the tips were measured by a tungsten-needle anode positioned above the tip apex. Tips decorated with tungsten nanoparticles demonstrated a smaller saturation region in current-voltage characteristics compared to the pristine tips. An emission activation process, which consisted in sudden current increase at certain value of applied voltage, was observed for the decorated silicon tips. This behavior was explained by the formation of vertical protrusions extending from the metal particles revealed by scanning electron microscopy after field emission experiments.}, language = {en} } @article{CheeKammlerGrahametal., author = {Chee, See Wee and Kammler, Martin and Graham, Jeremy and Gignac, Lynne and Reuter, Mark C. and Hull, Robert and Ross, Frances M.}, title = {Directed Self-Assembly of Ge Quantum Dots Using Focused Si2+ Ion Beam Patterning}, series = {scientific reports}, volume = {8}, journal = {scientific reports}, publisher = {Nature}, doi = {10.1038/s41598-018-27512-z}, pages = {1 -- 10}, abstract = {We show that templating a Si surface with a focused beam of Si2+ or Si+ ions can create suitable nucleation sites for the subsequent growth of self-assembled Ge quantum dots by chemical vapor deposition. To determine the mechanism of patterning we use atomic force microscopy to show that, similar to Ga+ patterning, the formation of a surface pit is required to enable control over Ge quantum dot locations. We find that relatively high implantation doses are required to achieve patterning, and these doses lead to amorphization of the substrate. We assess the degree to which the substrate crystallinity can be recovered by subsequent processing. Using in situ transmission electron microscopy heating experiments we find that recrystallization is possible at the growth temperature of the Ge quantum dots, but defects remain that follow the pattern of the initial implantation. We discuss the formation mechanism of the defects and the benefits of using Si ions for patterning both defects and quantum dots on Si substrates.}, language = {en} } @inproceedings{AllahamBuchnerSchreineretal., author = {Allaham, Mohammad M. and Buchner, Philipp and Schreiner, Rupert and Kn{\´a}pek, Alexandr}, title = {Testing the performance of Murphy-Good plots when applied to current-voltage characteristics of Si field electron emission tips}, series = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 5-9 July 2021, Lyon, France}, booktitle = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 5-9 July 2021, Lyon, France}, publisher = {IEEE}, doi = {10.1109/IVNC52431.2021.9600690}, pages = {1 -- 2}, abstract = {Murphy-Good plots are the most recent type of the analysis methods in the field electron emission theory, this type of plots has several useful characteristics such as: having the very-nearly straight line to represent the current-voltage characteristics and the absence of the correction factors in the mathematical procedure of the analysis process. In this study, n-type <111> and <100> Si chips containing four individual emitters are used as base emitters and mounted in a diode configuration field emission setup where the experiments are operated in an ultra-high vacuum ( 10-7 Pa). Each chip has four individual controllable emitters with 5 µm distance between the Si tips and the same material grid. Laser micromachining and subsequent wet chemical etching technique is used to structure and polish the tips. Murphy-Good plots are used to study the behavior of the Si individual tips and compare the results with the array current by extracting the field emission characterization parameters of the emitters.}, language = {en} }