Atomic Force Microscopy Support and Information

User Instruction

As a user facility, supplemental instruction of help is recommended for users conducting new experiments or modifying existing protocols.

In order to obtain additional training please contact Matthew Rush or Gabriel Montaño to schedule an appointment.

User Manuals

Supplemental material has also been developed for training and clarification:


Links to common solution video:



Asylum Customer Support

Asylum Support

Asylum Research has great customer support for users to ask questions.

Asylum Research also provides a forum for user inquiries and postings.

Users must register with the forum, but access is free.


Camera will not turn on

  • Be sure to select the camera icon within the Asylum software to bring up camera window
  • (If camera closed without closing “camera panel” camera icon will not work, close camera panel)
  • Check that light source (next to computer tower is on) and brightness knob turned up (in front of controller)
  • Check to be sure camera mount is aligned with mirror (mounted behind AFM head

Cannot align laser

Check controller to be sure laser (key) is on

When aligning laser please use centering method:

  1. Turn Y-laser wheel (PDY) one direction, all the way until it stops
  2. Count turns (PDY) while turning all the way the other direction = total working length
  3. Turn Y-laser wheel (PDY) until 1/2 total working length
  4. Repeat steps 1-3 with X-laser wheel (PDX)
  5. Laser should be somewhere near edge of probe/cantilever and with slight adjustments of PDX; and can be clearly seen if reflected off larger probe area (+ PDX)
  6. Move laser to base of cantilever
  7. Position (maximum sum) in Y-direction
  8. Then move (X-direction) to end of cantilever

Irregular thermal scan

Thermal scan is a survey of cantilever signal at all possible operating frequencies and is important in identifying specific cantilever resonance frequencies for non-contact/tapping modes of use.

Irregularities in Thermal scan can arise from:

  • Improper probe mounting (misaligned/loose) –> check probe seating in holder
  • Damaged tip/cantilever –> check for visual cracks in probe material
  • Fouled tip (excess weight on cantilever) –> clean probe with air/water
  • Laser/detector misalignment –> See Laser alignment FAQ

Irregular scan profile


Topographical scanning in non-contact/tapping mode relies on cantilever operation at resonant frequency to maintain regular oscillation of tip in the z-direction. Tip engagement with surface may alter this behavior and require re-tuning of tip.

Set Point:

Often when engaged signal quality may be too low for effective computer generation of topographical image. Lowering set-point allows for harder tip-surface contact and measurement of surface features. Note: set-point is relative to cantilever (sum) signal when not in contact with surface (“free air amplitude”). Low set-point relative to free air amplitude can result in harder contact with surface and blunting/damage to tip.


When engaged on surface the z-piezo controls tip approach or withdrawal form surface in order to maintain good contact. The amount/length of adjustment in the direction for tracking up and down vertical features is controlled by the Gain value. A high (>50) versus low (<5) gain value allows for greater step sizes when controller adjust tip in z-direction. This, however, is relative to how fast a scan is being conducted as slower scan speeds (≤5 nm/s) allow for greater time to climb up and down surface features. Hysteresis of drift between trace and retrace curves can be improved by increasing gain. Note: Higher gain results harder contact with surface and blunting/damage of tip.

Sinusoidal “noise”/Gain:

Gain can also result in the creation of additional noise in a scan through over/underestimating of necessary step length and repeated corrections to maintain good contact with surface. This typically results in the appearance of a sinusoidal waveform in image that is not actually there. Reducing gain will reduce or remove waveform all together.

Attractive/Repulsive imaging/Phase:

Tip-surface interaction can also play a critical role in image quality. Specifically phase shifting of tip when in close proximity to surface can effect attractive and repulsive interactions between tip-surface. “Attractive” forces can be observed when Phase is > 90˚, “repulsive” when < 90˚. Tuning typically attempts to center phase @ 90˚, but further adjustments can be made by altering "phase" offset during tuning.