LMA

AAHRUS VT-SPM

 

 AAHRUS VT-SPM

 

AahrusThe Aahrus is a combined STM and non-contact AFM head which operates a KolibriTM sensor under Ultra-high-vacuum conditions (P<10-10 mbar). Apart from allowing for imaging of metallic and insulating samples with atomic resolution, its unique feature is a radiative filament which can heat the sample up to 900ºC while keeping the tip and scanner protected near room temperature. This accessory, together with the possibility of dosing gases and evaporating materilas in-situ during scanning, makes the Aahrus an excellent instrument to explore the real-time chemical and catalytical activity of a surface by bringing the system to artificial thermodynamic conditions which can be tuned to the particular time resolution required for each experiment.

The microscope is connected under UHV conditions to the JT-STM facility, which offers all kind of sample preparation accessories and allows users to exchange the very same sample between both microscopes. The Aahrus is regularly applied to real-time monitoring of thermally activated processes such as chemical vapour deposition (for instance graphene growth on metallic surfaces), on-surface synthesis, metal epitaxy and self-assembled organic monolayers.





What kind of information can be obtained with these instruments?

Scanning Probe Microscopy and spectroscopy:

  • Structural characterization with atomic resolution of metallic and insulating surfaces.
  • Fast loading approach and flexible design for quick characterization of samples grown in-situ or taken as-prepared from the outside.
  • Force spectroscopy with sub-Å Z resolution
  • Chemical contrast mapping with atomic resolution using repulsive or attracting tip-atom forces.
  • Dedicated Kelvin Probe Microscopy module.

 

Real-time physical-chemical characterization of 2D materials:

  • Real-time monitoring of surface dynamics up to 900 ºC
  • Controlled gas-dosing in-situ during scanning.
  • Capable of scanning during evaporation of organic or inorganic materials.

Technical specifications

Temperature range: 100 (LN2 flow cryostat) to 1200 K (radiative heater)

LN2 hold time: 24 hours

Z topographic noise: 5 pm peak-peak; <2000 fm/ÖHz

Thermal drift at low temperatures: Standard STM grade images can be obtained with scan time <5 min at temperatures <250 K.

Thermal drift at high temperatures: For T<600 ºC standard STM grade images can be obtained after thermal relaxation of about 15 min. For 600 ºC < T < 900 ºC scan time is limited to 5-10 minutes.

Minimum stable oscillation amplitude of Kolibri sensor for nc-AFM: 90 pm

Force resolution: <1 pN

Maximum operating pressure: 1´10-5 mbar.

In-situ tip conditioning

 

Sample preparation: (shared with SPECS JT-STM) 3 ion-guns, 3 e-beam heaters (100-1300ºC). 1 flash heater (>2000 ºC in 25 seconds), low energy electron diffraction and Auger spectroscopy (SPECS ErLEED 150), quadrupole mass spectrometer for residual gas analysis, 7 leak-valves for controlled gas injection, 1 SPECS EBE4 and 1 SPECS EBE1 e-beam evaporators, 2 parking stations for mini-UHV transportable organic evaporators, 1 high temperature effusion cell (CreaTec)

 

Imágenes