The AFM is used for a variety of applications, including topographical imaging, mechanical property measurement, and electrical property measurement. The cantilever tip scans the surface of the sample, and the deflection is measured using a laser that reflects off the back of the cantilever into a photodetector. The data is then processed by the control software to generate detailed images or to analyze the properties of the sample. The high sensitivity of the photodetector and the feedback loop allows for sub-nanometer resolution, making AFM a powerful tool for nanoscale measurements.
Technical Specifications
Cantilever Specifications:
The cantilevers are usually made of Silicon or Silicon Nitride and have a spring constant ranging from 0.2 to 48 N/m. The resonant frequency of these cantilevers can vary between 10 to 300 kHz, and the tip radius is generally less than 10 nm.
Piezoelectric Scanner:
The scanner has a scan range of up to 100 µm x 100 µm x 15 µm in the XYZ directions. It offers sub-nanometer resolution and has a linearity error of less than 0.5%.
Laser Source:
The laser used in AFM typically has a wavelength between 630-670 nm and a power range of 1-5 mW.
Photodetector:
A quadrant photodiode is generally used as the photodetector, which has a sensitivity of around 0.1 nm.
Feedback Loop:
The feedback loop has a bandwidth of up to 10 MHz and noise levels of less than 0.1 nm.
Control Software:
The control software can acquire data at a rate of up to 10 MS/s and can generate images with up to 4096 x 4096 pixels.
