Atomic Resolution without Damping Systems

Fig.1: Scanner tube with scanning tip

Fig.2: Complete Mini-STM

Fig.3: Phthalocyanin molecule on a carpet of carbon atoms

Fig.4: Surface of highly orientated pyrolytic graphite

Fig. 5: Atomic structures of a gold surface

Fig.6: Expanded view of the superlatice

Fig.7: Bit structure on a CD

Fig.8: Structure written into a high-temperature semiconductor with the STM (300x300nm)

This is the world's smallest commercial scanning tunneling microscope (STM). Its heart is formed by the Nanomotor. The sample lies on top of three balls mounted on the scanner tube.

The complete Mini STM fits under a thimble and is thus very insensitive to environmental vibrations. No additional vibration damping systems are needed.

Figure 3 shows a phthalocyanin molecule lying on a carpet of carbon atoms (Highly Oriented Pyrolytic Graphite, HOPG). The distance between two visible atoms of this carpet is 0.25 nm. This picture was taken without additional vibration damping.

The Mini STM can also be used to write structures on surfaces. The Mini STM is available with complete control electronics and Windows-based control program.

Below you see some results derived from different applications of the Mini-STM:

At the University
Figure 4 shows a HOPG-surface (Highly-Orientated Pyrolytic Graphite), featuring the individual atoms in their hexagonal lattice. The scanned area is about 1.8 x 1.8 nm2.
This image was taken by a group of students doing a practical physics laboratory course at the University of Aachen (RWTH) with the microscope located on a regular office desk on the 3rd floor of the University building.

On the road
Figure 5 and 6 show the atomic superlattice of a gold surface. They were taken by a customer (Institut für Experimentalphysik, FU Berlin) at the Hannover fair 1998, the biggest industrial fair in Germany. The Mini-STM without any vibration damping system sat on an exhibit table placed on a wooden floor covering electrical cables. Visitors walked over this floor, causing no visible effects in the scanned pictures of a gold sample, not even during low speed scans of large sample areas. The insensitivity of the Mini-STM to vibrations is made possible by the small size, and this is only possible by using a Nanomotor.

Longer Tube Scanner (Fig. 7)
This picture of CD bits was taken with a Tube Scanner Head "Tall" having the same diameter as that of the Mini-STM, but twice the length. The stability decreases but with our high voltage amplifiers a scanning range of up to 20 µm is possible. The same head is used for the SNOM.

The STM can also be used to write structures:
The "Phi" in Fig. 8 was written directly into a High Temperature Superconductor and visualized at the same time in the same device: an STM (2. Physikal. Institut, RWTH Aachen). This structure can be treated to form a superconductor, conductor or insulator. Since the structures are extremely small they can form quantum mechanical devices, e.g. Josephson Contacts, tunneling devices or Superconducting Quantum Interference Devices (SQUID). Until now SQUID's have been made by several complex lithographic steps in a process having a poor yield. This technique was patented in co-operation with the RWTH-Aachen. The structures can be made and visualized without expensive equipment "on a normal table".

  • atomic resolution
  • less than 50 mm x 50mm x 80mm in size
  • needs no additional damping systems
  • all Nanomotor driven positioners can form SPM heads
Example applications:
Other sources of information:

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