Paper
17 September 2013 Pulsed laser deposited cobalt-doped ZnO thin film
Author Affiliations +
Proceedings Volume 8904, International Symposium on Photoelectronic Detection and Imaging 2013: High Power Lasers and Applications; 890402 (2013) https://doi.org/10.1117/12.2030394
Event: ISPDI 2013 - Fifth International Symposium on Photoelectronic Detection and Imaging, 2013, Beijing, China
Abstract
To realize the room-temperature ferromagnetism (RTFM) in diluted magnetic semiconductors (DMS), we prepared a series of Cobalt-doped ZnO thin films using pulsed laser deposition (PLD) at deposition temperatures 500°C under oxygen pressure from 2.5×10-4 Pa to 15 Pa. To elucidate the physical origin of RTFM, Co 2p spectra of cobalt-doped ZnO thin films was measured by X-ray photoelectron spectroscopy (XPS). The magnetic properties of films were measured by an alternating gradient magnetometer (AGM), and the electrical properties were detected by a Hall Effect instrument using the Van der Pauw method. XPS analysis shows that the Co2+ exists and Co clusters and elemental content change greatly in samples under various deposition oxygen pressures. Not only the valence state and elemental content but also the electrical and magnetic properties were changed. In the case of oxygen pressure 10 Pa, an improvement of saturation magnetic moment about one order of magnitude over other oxygen pressure experiments, and the film exhibits ferromagnetism with a curie temperature above room temperature. It was found that the value of carrier concentration in the Co-doped ZnO film under oxygen pressure 10Pa increases about one order of magnitude than the values of other samples under different oxygen pressure. Combining XPS with AGM measurements, we found that the ferromagnetic signals in cobalt-doped ZnO thin film deposited at 500 °C under oxygen pressure 10 Pa only appear with the detectable Co2+ spectra from incompletely oxidized Co metal or Co cluster. So oxygen pressure 10 Pa can be thought the best condition to obtain room-temperature dilute magnetic semiconductor about cobalt-doped ZnO thin films.
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Li Wang, Xue-qiong Su, Yi Lu, and Jiang-bo Chen "Pulsed laser deposited cobalt-doped ZnO thin film", Proc. SPIE 8904, International Symposium on Photoelectronic Detection and Imaging 2013: High Power Lasers and Applications, 890402 (17 September 2013); https://doi.org/10.1117/12.2030394
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KEYWORDS
Cobalt

Oxygen

Thin films

Zinc oxide

Protactinium

Magnetism

Magnetic semiconductors

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