Intermodulation Products AB

Solna, Sweden

Intermodulation Products AB

Solna, Sweden
SEARCH FILTERS
Time filter
Source Type

Tholen E.A.,Intermodulation Products AB | Tholen E.A.,KTH Royal Institute of Technology | Platz D.,KTH Royal Institute of Technology | Forchheimer D.,KTH Royal Institute of Technology | And 6 more authors.
Review of Scientific Instruments | Year: 2011

Nonlinear systems can be probed by driving them with two or more pure tones while measuring the intermodulation products of the drive tones in the response. We describe a digital lockin analyzer which is designed explicitly for this purpose. The analyzer is implemented on a field-programmable gate array, providing speed in analysis, real-time feedback, and stability in operation. The use of the analyzer is demonstrated for intermodulation atomic force microscopy. A generalization of the intermodulation spectral technique to arbitrary drive waveforms is discussed. © 2011 American Institute of Physics.


Forchheimer D.,KTH Royal Institute of Technology | Platz D.,KTH Royal Institute of Technology | Tholen E.A.,Intermodulation Products AB | Haviland D.B.,KTH Royal Institute of Technology
Applied Physics Letters | Year: 2013

We demonstrate quantitative force imaging of long-range magnetic forces simultaneously with near-surface van-der-Waals and contact-mechanics forces using intermodulation atomic force microscopy. Magnetic forces at the 200 pN level are separated from near-surface forces at the 30 nN level. Imaging of these forces is performed in both the contact and non-contact regimes of near-surface interactions. © 2013 AIP Publishing LLC.


Forchheimer D.,KTH Royal Institute of Technology | Platz D.,KTH Royal Institute of Technology | Tholen E.A.,Intermodulation Products AB | Haviland D.B.,KTH Royal Institute of Technology
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We present a method to reconstruct the nonlinear tip-surface force and extract material properties from a multifrequency atomic force microscopy (AFM) measurement with a high-quality-factor cantilever resonance. In a measurement time of ∼2 ms, we are able to accurately reconstruct the tip-surface force-displacement curve, allowing simultaneous high-resolution imaging of both topography and material properties at typical AFM scan rates. We verify the method using numerical simulations, apply it to experimental data, and use it to image mechanical properties of a polymer blend. We further discuss the limitations of the method and identify suitable operating conditions for AFM experiments. © 2012 American Physical Society.


Borysov S.S.,KTH Royal Institute of Technology | Platz D.,KTH Royal Institute of Technology | De Wijn A.S.,University of Stockholm | Forchheimer D.,KTH Royal Institute of Technology | And 4 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We propose a theoretical framework for reconstructing tip-surface interactions using the intermodulation technique when more than one eigenmode is required to describe the cantilever motion. Two particular cases of bimodal motion are studied numerically: one bending and one torsional mode, and two bending modes. We demonstrate the possibility of accurate reconstruction of a two-dimensional conservative force field for the former case, while dissipative forces are studied for the latter. © 2013 American Physical Society.


Sanandaji N.,KTH Royal Institute of Technology | Oko A.,Swedish Institute for Surface Chemistry | Haviland D.B.,KTH Royal Institute of Technology | Tholen E.A.,Intermodulation Products AB | And 2 more authors.
European Polymer Journal | Year: 2013

Inkjet printing is a technique for the precise deposition of liquid droplets in the pL-volume range in well-defined patterns. Previous studies have shown that inkjet printing is attractive in polymer technology since it permits the controlled deposition of functional polymer surfaces. We suggest that the technique might also be useful for studying crystallization, in particular confined crystallization. Inkjet printing is a non-contact deposition method with minimal risk of contamination, which allows the exact deposition of both polymer solutions and polymer melts. This paper demonstrates the possibility of utilizing the technique to create surfaces where polymer chains form isolated small structures. These structures were confined by both the low polymer content in each droplet and the time constraint on crystal formation that arose as the result of the rapid solvent evaporation from the pL-sized droplets. In theory, inkjet printing enables the exact deposition of systems with as few as a single polymer chain in the average droplet. With appropriate instrumentation, the versatile inkjet technology can be utilized to create whole surfaces covered with polymer structures formed by the crystallization of small, dilute and rapidly evaporating droplets. 110 pL droplets of a 10-6 g L -1 poly(caprolactone) solution in 1-butanol have been deposited and studied by atomic force microscopy. Small structures of ca. 10 nm thickness and ca. 50 nm diameter also seemed to exhibit crystalline features. Some of the small structures had unusual rectangular forms whilst others were interpreted to be early precursors to six-sided single crystals previously observed for poly(caprolactone). The unusual forms observed may have resulted from the entrapment of crystal structures into metastable phases, due to the limited amount of polymer material present and the rapid evaporation of the droplets.© 2012 Elsevier Ltd. All rights reserved.


Bergqvist J.,Linköping University | Tholen E.A.,Intermodulation Products AB | Inganas O.,Linköping University
Solar Energy Materials and Solar Cells | Year: 2016

Thin film solar cells, and in particular printed organic solar cells, offer a potential route to a low cost power generation from sunlight. However, manufacturing these solar cells rapidly generates large areas that have to be characterized, preferably in-line for a direct feed back to the development and production process. Here we introduce the LEDimage, a LED array illumination induced photocurrent method suitable for high speed in-line characterization and defect detection of organic solar cell modules. Each LED in the array is amplitude modulated at an individual frequency and photo current maps are generated by analyzing the photo current response with a multifrequency lock-in amplifier. For monolithic series connected modules the LEDimage enables simultaneous illumination of all series connected subcells without additional bias light. Furthermore, the LEDimage can be used as a hand scanner for fast device characterization and also as a portable photocurrent mapping tool. Upscaled and with improved in-line contacts we expect that LEDimage can be an effective research and industry tool for characterization of large area thin film solar cells at high speeds. © 2016 Elsevier B.V.


Platz D.,Albanova University Center | Forchheimer D.,Albanova University Center | Tholen E.A.,Intermodulation Products AB | Haviland D.B.,Albanova University Center
Nature Communications | Year: 2013

Knowledge of surface forces is the key to understanding a large number of processes in fields ranging from physics to material science and biology. The most common method to study surfaces is dynamic atomic force microscopy (AFM). Dynamic AFM has been enormously successful in imaging surface topography, even to atomic resolution, but the force between the AFM tip and the surface remains unknown during imaging. Here we present a new approach that combines high-accuracy force measurements and high-resolution scanning. The method, called amplitude-dependence force spectroscopy (ADFS), is based on the amplitude dependence of the cantilever's response near resonance and allows for separate determination of both conservative and dissipative tip-surface interactions. We use ADFS to quantitatively study and map the nano-mechanical interaction between the AFM tip and heterogeneous polymer surfaces. ADFS is compatible with commercial atomic force microscopes and we anticipate its widespread use in taking AFM toward quantitative microscopy. © 2013 Macmillan Publishers Limited. All rights reserved.


Platz D.,Albanova University Center | Forchheimer D.,Albanova University Center | Tholen E.A.,Intermodulation Products AB | Haviland D.B.,Albanova University Center
Beilstein Journal of Nanotechnology | Year: 2013

Intermodulation atomic force microscopy (ImAFM) is a mode of dynamic atomic force microscopy that probes the nonlinear tip-surface force by measurement of the mixing of multiple modes in a frequency comb. A high-quality factor cantilever resonance and a suitable drive comb will result in tip motion described by a narrow-band frequency comb. We show, by a separation of time scales, that such motion is equivalent to rapid oscillations at the cantilever resonance with a slow amplitude and phase or frequency modulation. With this time-domain perspective, we analyze single oscillation cycles in ImAFM to extract the Fourier components of the tip-surface force that are in-phase with the tip motion (FI) and quadrature to the motion (FQ). Traditionally, these force components have been considered as a function of the static-probe height only. Here we show that FI and FQ actually depend on both static-probe height and oscillation amplitude. We demonstrate on simulated data how to reconstruct the amplitude dependence of FI and FQ from a single ImAFM measurement. Furthermore, we introduce ImAFM approach measurements with which we reconstruct the full amplitude and probe-height dependence of the force components FI and FQ, providing deeper insight into the tip-surface interaction. We demonstrate the capabilities of ImAFM approach measurements on a polystyrene polymer surface. © 2013 Platz et al.


Platz D.,Albanova University Center | Forchheimer D.,Albanova University Center | Tholen E.A.,Intermodulation Products AB | Haviland D.B.,Albanova University Center
Beilstein Journal of Nanotechnology | Year: 2013

We present polynomial force reconstruction from experimental intermodulation atomic force microscopy (ImAFM) data. We study the tip-surface force during a slow surface approach and compare the results with amplitude-dependence force spectroscopy (ADFS). Based on polynomial force reconstruction we generate high-resolution surface-property maps of polymer blend samples. The polynomial method is described as a special example of a more general approximative force reconstruction, where the aim is to determine model parameters that best approximate the measured force spectrum. This approximative approach is not limited to spectral data, and we demonstrate how it can be adapted to a force quadrature picture. © 2013 Gupta et al; licensee Beilstein-Institut.

Loading Intermodulation Products AB collaborators
Loading Intermodulation Products AB collaborators