Enhancing AFM
Speeding up an AFM measurement by altering the Q factor
R.H.A. Swuste (TU Delft - Mechanical Engineering)
J.F.L. Goosen – Mentor
Maarten van Es – Mentor
B Sajadi – Coach
Murali K. Ghatkesar – Coach
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Abstract
The Atomic Force Microscope (afm) is a small scale measuring device, with a lot of benefits over other existing measuring techniques. Unfortunately, measurement speed is not one of them. Many have tried and succeeded to improve the measurement speed, but there is still room for improvement.
By passively lowering the Q-factor, a measurement can be sped up, while still be compatible with other speed improvement techniques.
To passively lower the Q-factor, we propose measuring in a medium more dense then air. First in a liquid, de-mineralized water, to prove the effect, and later in a gas, co2, to keep the samples clean.
Our models predict a speed increase of 0.3559 ms per measured point, or 6.941 min per image of 5 μm × 5 μm with 512 lines in liquid. The experiments show an increase of 0.4180 ms per point, or 8.155 min per measurement. In the much less dense gas a 0.031 01 ms per point or 0.6550 min per frame is calculated. The experiments show an increase of 0.027 29 ms per point with a total of 0.5300 min per frame.
Both in liquid and in gas an improvement is observed. When measuring in a liquid, the speed increase of 8.155 min per frame is noticeable when a small area on a single sample is measured. Measurements in gas, with an increase of 0.5300min per frame only become interesting when multiple frames need to be measured, since a gas measurement does take longer to set up. Changing the used measurement gas to a more dense gas could make single frame measurements more interesting.