I am a PhD student in the science group Complex Materials and Devices. Originally I am from Lycksele (Sweden) but I did my studies in Applied Physics and Electrical Engineering, with specialization in Nano and Material Physics, here at Linköping University. In the CoMaDe group I am investigating ratchet structures for potential use in energy harvesting.

On/off ratchets


Figur 1The most common type of ratchet is an on/off ratchet which generates a sawtooth potential in its “on”-state and a flat potential in its “off”-state. Here, the idea is that particles are localized in the potential wells when the potential is on. When the potential is off, the particles will diffuse and spread over a wider area. Consequently, when the potential is turned on again, re-forming the sawtooth potential, the particles that had diffused over an edge will drift to the bottom of the re-formed well. Because of the asymmetric shape of these wells, a net motion is achieved by periodically turning on and off the potentials. [1]

Rectification of electromagnetic radiation

Figur 2

An example of a non-directional perturbation is an alternating electric field; rectification of this might find use in e.g. novel RF antennas. When we subject charges (electrons or holes) that sit in a periodic asymmetric channel, i.e. a ratchet, the asymmetry will result in a net DC current that can power electric circuitry. The effect can be investigated for materials with different mobility and the charge carrier densities can be controlled via doping and/or a gate field in a so-called field effect transistor.

[1] Appl. Phys. Lett. 102, 073104 (2013) doi: 10.1063/1.4793198



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Molecular Doping and Trap Filling in Organic Semiconductor Host-Guest Systems

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Article in journal


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