Spectrum digitizer helps developers improve atomic force microscope performance

Hansdorf, Germany, March 2, 2021 – Atomic force microscopy (AFM) is one of the most important tools in materials science for mechanically scanning surface topography. AFM can measure the interaction force between nanoprobes and atomic surfaces with a resolution of only a fraction of a nanometer. Currently, the University of Newcastle, Australia, is improving and simplifying these complex equipment to expand the wide application of atomic force microscopy in laboratories around the world. In this study, a high-precision 8-channel Spectrum digitizerNETBOX advances the AFM project.

The first atomic force microscope (AFM) was developed in 1985 and has since become an important tool in the study of surface chemistry in laboratories around the world. The resolution of AFM is 1000 times that of conventional optical microscopes, and its excellent resolution can reveal more details. Unlike electron microscopes and other advanced systems, AFM is capable of not only in situ imaging, but also topography imaging and force measurement, making it ideal for the study of soft biomaterials, polymers, nanostructures, and a variety of other materials.

Spectrum digitizer helps developers improve atomic force microscope performance

Dr. Ruppert’s modified cantilever

Key elements of AFM systems have been researched at Newcastle University to improve the overall performance of these microscopes while simplifying operation. The Precision Mechatronics Laboratory in the University’s School of Electrical Engineering and Computing brings together expertise in nanotechnology, mechatronics, microelectromechanical systems (MEMS), and low-noise Electronic design, and has created tools to simplify AFM complexity and reduce Unique solution for cost.

Spectrum digitizer helps developers improve atomic force microscope performance

Schematic of a conventional multi-frequency AFM experiment: as the nanopositioner scans the sample, the cantilever vibrates simultaneously at multiple resonant frequencies

AFM typically generates topographic images by scanning a sample surface with a cantilever or probe. Subsequently, small changes in the deflection of the cantilever are determined by a laser beam and a position-sensitive photodiode detector. The three-dimensional topography is created by acquiring and analyzing the signal from the detector to determine the topological height change of the sample surface.

At the heart of the instrument is a microcantilever that interacts with the sample and provides the “physical link” for measuring nanomechanical properties. Although the cantilever micromachining technology has improved over the years, the overall design has not changed much, so the passive rectangular cantilever is now widely used as a standard in the industry. Traditional cantilevered instruments require an external piezoelectric acoustic sensor and an external optical deflection sensor. Neither component performs ideally for the multi-frequency AFM technology trend, because the imaging information of multi-frequency AFM technology can also be extended to a range of nanomechanical properties including sample hardness, elasticity, and adhesion. . In contrast, active cantilevers with chip-scale integrated drivers and sensors offer many advantages over conventional cantilevers, including structural modes without mounting systems, downscaling, single-chip AFM, parallel cantilever arrays, and no light-wave interference.

Spectrum digitizer helps developers improve atomic force microscope performance

Dr. Michael Ruppert is improving custom cantilevers in atomic force microscopes

Dr. Ruppert and colleagues have recently published several papers proposing integrated cantilever solutions for improving AFM performance, simplifying operation, and reducing equipment cost. Topics discussed in the paper include innovative cantilever designs that optimize deflection sensitivity, enable arbitrary resonant frequency layouts, and enable the integration of robust multi-mode Q-control. In collaboration with the University of Texas at Dallas, Dr. Ruppert also co-developed the first silicon-on-insulator, single-chip microelectromechanical system AFM, which features the integration of planar electrostatic actuators with electrothermal sensors, as well as the An externally driven AIN piezoelectric layer is integrated with deflection sensing. This method shows great potential for significantly reducing AFM cost, simplifying operational complexity, and expanding product application range.

This type of research relies on high-precision measurement equipment to acquire and analyze sensor signals from integrated cantilevers. By determining the amplitude noise spectral density, important parameters such as the thermal noise at resonance of the cantilever system, the cantilever tracking bandwidth and the electronic noise floor of the instrument can be obtained. For this, the research team used a DN2.593-08 digitizerNETBOX model from Spectrum Instruments. The device has 8 fully synchronized digitized channels, each capable of sampling signals at 16-bit resolution and 40MS/s. For control and data transmission, the digtizerNETBOX is also connected to the host computer via a simple Gbit Ethernet connection.

DN2.593-08 digtizerNETBOX is capable of sampling 8 simultaneous channels at 40MS/s and 16-bit resolution

Researcher Dr. Michael Ruppert said: “The digitizerNETBOX is an important measurement tool in precision mechatronics laboratories. This device is capable of simultaneously producing high resolution under low-noise testing of multiple integrated sensor fields to meet the performance demands of our system. “

About Spectrum Instruments

Founded in 1989, Spectrum Instruments has designed and developed several modular digitizer and generator products to date, including PC cards (PCIe and PXIe) and standalone Ethernet devices (LXI). Over the past 30 years, Spectrum has been widely recognized in the industry, and its products are also used in many products and research projects of industry leaders and leading universities. Headquartered in Hansdorf near Hamburg, Germany, Spectrum Instruments has a worldwide reputation for technical excellence and excellent customer service.For more information, please visit the official websitewww.spectrum-instrumentation.com.

The Links:   DMF50036 SEMIX353GB126V1

Bookmark the permalink.

Comments are closed.