Final Report Summary - VIN (Video-rate Scanning Probe Microscopy Imaging of Nanostructures on Surfaces)
Instrumentation development
The in-house development of scanning-probe instrumentation, including mechanical and electronic design, construction, testing, and software development have been possible through close collaboration between technically oriented scientific staff and our highly skilled mechanical and electronics workshops. Today, the world-renowned Scanning Tunneling Microscope design used in my laboratory has been commercialized in an almost 1:1 edition by the German scientific-instrument manufacturer SPECS GmbH as the “Aarhus STM” ( http://www.specs.de/cms/front_content.php?idcat=241 ).
Within the VIN project, we first shifted the mechanical resonances in the scanning part of the Scanning Tunneling Microscope further up in frequency. This step was crucial for stable high-resolution imaging at high scanning speeds, since otherwise mechanical resonances (transverse or longitudinal) excited by the imposed scanning frequency will lead to dramatic fluctuations in the tunneling current between the tip and the sample. This was mainly an exercise in miniaturization, starting from the already quite small scanner tube of the Aarhus STM. Accordingly, we had to design new high-precision components, conceptually not very different from the existing design, but about 50% smaller in size, and modify the existing methods used to solder and glue the tube assembly together. Secondly, we completed a new design of the STM control electronics. This was another major undertaking involving the implementation of the USB2 protocol and adjoining hardware for data transmission and a new pre-amplifier design. The interface between control electronics and computer is now entirely USB-based, allowing us to use any computer with the new software to control the STM. This constitutes an important step away from dedicated control computers with special STM controller cards. With the newly designed fast-scanning STM we can scan at unprecedented speeds up to 110 frames / sec for small STM images (See http://phys.au.dk/forskning/condensed-matter-physics/spm/the-aarhus-stm/video-rate-stm/ where also a block diagram of the new electronic interface can be found).
Fundamental science projects
The in-house constructed electronics described above has been implemented to control the STM’s in several existing ultra-high vacuum chambers as well as the STM using the new scanner-tube design. We have used the fast-scanning STM in the following science projects:
1. Reactivity of oxide surfaces
2. Hydrodesulphurization (HDS) catalysis
3. Self-assembly mechanisms of organic molecules
Knowledge and technology transfer
Since many years a fruitful collaboration exists between my group and the German instrument manufacturer SPECS GmbH. In the beginning of the project the company has sent technical staff to my laboratories to learn directly from the people involved in the design and construction of the Aarhus STM and adjoining hardware and software. This has ensured fast knowledge and technology transfer and enabled unusually fast commercialization of the newly developed instrumentation. Today, a high-temperature version and a high-pressure version of the Aarhus STM have been released.
The in-house development of scanning-probe instrumentation, including mechanical and electronic design, construction, testing, and software development have been possible through close collaboration between technically oriented scientific staff and our highly skilled mechanical and electronics workshops. Today, the world-renowned Scanning Tunneling Microscope design used in my laboratory has been commercialized in an almost 1:1 edition by the German scientific-instrument manufacturer SPECS GmbH as the “Aarhus STM” ( http://www.specs.de/cms/front_content.php?idcat=241 ).
Within the VIN project, we first shifted the mechanical resonances in the scanning part of the Scanning Tunneling Microscope further up in frequency. This step was crucial for stable high-resolution imaging at high scanning speeds, since otherwise mechanical resonances (transverse or longitudinal) excited by the imposed scanning frequency will lead to dramatic fluctuations in the tunneling current between the tip and the sample. This was mainly an exercise in miniaturization, starting from the already quite small scanner tube of the Aarhus STM. Accordingly, we had to design new high-precision components, conceptually not very different from the existing design, but about 50% smaller in size, and modify the existing methods used to solder and glue the tube assembly together. Secondly, we completed a new design of the STM control electronics. This was another major undertaking involving the implementation of the USB2 protocol and adjoining hardware for data transmission and a new pre-amplifier design. The interface between control electronics and computer is now entirely USB-based, allowing us to use any computer with the new software to control the STM. This constitutes an important step away from dedicated control computers with special STM controller cards. With the newly designed fast-scanning STM we can scan at unprecedented speeds up to 110 frames / sec for small STM images (See http://phys.au.dk/forskning/condensed-matter-physics/spm/the-aarhus-stm/video-rate-stm/ where also a block diagram of the new electronic interface can be found).
Fundamental science projects
The in-house constructed electronics described above has been implemented to control the STM’s in several existing ultra-high vacuum chambers as well as the STM using the new scanner-tube design. We have used the fast-scanning STM in the following science projects:
1. Reactivity of oxide surfaces
2. Hydrodesulphurization (HDS) catalysis
3. Self-assembly mechanisms of organic molecules
Knowledge and technology transfer
Since many years a fruitful collaboration exists between my group and the German instrument manufacturer SPECS GmbH. In the beginning of the project the company has sent technical staff to my laboratories to learn directly from the people involved in the design and construction of the Aarhus STM and adjoining hardware and software. This has ensured fast knowledge and technology transfer and enabled unusually fast commercialization of the newly developed instrumentation. Today, a high-temperature version and a high-pressure version of the Aarhus STM have been released.