On the role of minority carriers in the frequency dependence of organic magnetoresistance
| Autor: | B Bert Koopmans, W Wiebe Wagemans, Martijn Kemerink, W. Verhoeven, P Paul Janssen, van der Ehm Ilse Heijden |
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| Přispěvatelé: | Physics of Nanostructures, Applied Physics and Science Education, Molecular Materials and Nanosystems, Eindhoven Hendrik Casimir institute |
| Rok vydání: | 2011 |
| Předmět: |
Electron mobility
Condensed matter physics Magnetoresistance Chemistry business.industry Mechanical Engineering Metals and Alloys Transit time Frequency dependence Condensed Matter Physics Electronic Optical and Magnetic Materials Magnetic field Organic semiconductor Optics Mechanics of Materials Materials Chemistry Charge carrier Thin film business |
| Zdroj: | Synthetic Metals, 161(7-8), 617-621. Elsevier |
| ISSN: | 0379-6779 |
| DOI: | 10.1016/j.synthmet.2011.01.013 |
| Popis: | In this work we investigate the frequency dependence of organic magnetoresistance (OMAR) both in small molecule-based (Alq3) and polymer (PPV derivative) materials, and investigate its thickness dependence. For all devices, we observed a strong decrease in magnetoconductance (MC) with increasing frequency of the ac component of the applied magnetic field. Moreover, we observed a strong reduction of the cut-off frequencies for increasing film thickness. By means of admittance spectroscopy and device simulations, we show that the cut-off frequency is related to the inverse transit time of the minority charge carriers. These observations confirm the important role of minority carriers in OMAR, and show that changes in OMAR are not only due to microscopic mechanisms, but also device physics is of significant relevance. Keywords: Organic semiconductor; Magnetoresistance; Carrier mobility; Minority carriers; Transit time |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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