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de Voogd JM, van Spronsen MA, Kalff FE, Bryant B, Ostojić O, den Haan AMJ, Groot IMN, Oosterkamp TH, Otte AF, Rost MJ. Fast and reliable pre-approach for scanning probe microscopes based on tip-sample capacitance. Ultramicroscopy 2017; 181:61-69. [PMID: 28525802 DOI: 10.1016/j.ultramic.2017.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/20/2017] [Accepted: 05/09/2017] [Indexed: 10/19/2022]
Abstract
Within the last three decades Scanning Probe Microscopy has been developed to a powerful tool for measuring surfaces and their properties on an atomic scale such that users can be found nowadays not only in academia but also in industry. This development is still pushed further by researchers, who continuously exploit new possibilities of this technique, as well as companies that focus mainly on the usability. However, although imaging has become significantly easier, the time required for a safe approach (without unwanted tip-sample contact) can be very time consuming, especially if the microscope is not equipped or suited for the observation of the tip-sample distance with an additional optical microscope. Here we show that the measurement of the absolute tip-sample capacitance provides an ideal solution for a fast and reliable pre-approach. The absolute tip-sample capacitance shows a generic behavior as a function of the distance, even though we measured it on several completely different setups. Insight into this behavior is gained via an analytical and computational analysis, from which two additional advantages arise: the capacitance measurement can be applied for observing, analyzing, and fine-tuning of the approach motor, as well as for the determination of the (effective) tip radius. The latter provides important information about the sharpness of the measured tip and can be used not only to characterize new (freshly etched) tips but also for the determination of the degradation after a tip-sample contact/crash.
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Affiliation(s)
- J M de Voogd
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
| | - M A van Spronsen
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - F E Kalff
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - B Bryant
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands; High Field Magnet Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - O Ostojić
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - A M J den Haan
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - I M N Groot
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands; Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, the Netherlands
| | - T H Oosterkamp
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - A F Otte
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - M J Rost
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
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den Haan AMJ, Wijts GHCJ, Galli F, Usenko O, van Baarle GJC, van der Zalm DJ, Oosterkamp TH. Atomic resolution scanning tunneling microscopy in a cryogen free dilution refrigerator at 15 mK. Rev Sci Instrum 2014; 85:035112. [PMID: 24689625 DOI: 10.1063/1.4868684] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Pulse tube refrigerators are becoming more common, because they are cost efficient and demand less handling than conventional (wet) refrigerators. However, a downside of a pulse tube system is the vibration level at the cold-head, which is in most designs several micrometers. We implemented vibration isolation techniques which significantly reduced vibration levels at the experiment. These optimizations were necessary for the vibration sensitive magnetic resonance force microscopy experiments at milli-kelvin temperatures for which the cryostat is intended. With these modifications we show atomic resolution scanning tunneling microscopy on graphite. This is promising for scanning probe microscopy applications at very low temperatures.
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Affiliation(s)
- A M J den Haan
- Department of Interface Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, The Netherlands
| | - G H C J Wijts
- Department of Interface Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, The Netherlands
| | - F Galli
- Department of Interface Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, The Netherlands
| | - O Usenko
- Leiden Cryogenics, Kenauweg 11, 2331BA Leiden, The Netherlands
| | - G J C van Baarle
- Leiden Spin Imaging (LSI), J.H. Oortweg 21, 2333CH Leiden, The Netherlands
| | - D J van der Zalm
- Leiden Spin Imaging (LSI), J.H. Oortweg 21, 2333CH Leiden, The Netherlands
| | - T H Oosterkamp
- Department of Interface Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, The Netherlands
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