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Optical and magnetooptical properties of the p-type ZnMnO.

Ewa Przezdziecka 1Eliana Kaminska 2Michal Kiecana 1Maciej Sawicki 1Lukasz Klopotowski 1Wojciech Pacuski 4Elzbieta Dynowska 1Witold Daniel Dobrowolski 1Jacek Kossut 3

1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
2. Institute of Electron Technology (ITE), al. Lotników 32/46, Warszawa 02-668, Poland
3. Polish Academy of Sciences, Institute of Physics and ERATO Semiconductor Spintronics Project, al. Lotników 32/46, Warszawa 02-668, Poland
4. Warsaw University, Faculty of Physics, Hoża 69, Warszawa 00-681, Poland

Abstract

Zinc oxide is an II-VI compound semiconductor with a wide direct band gap of 3.37 eV at room temperature. Undoped ZnO is usually n-type, which is associated with native point defects and/or residual hydrogen. On the other hand, Mn doped p-type ZnO is predicted to be ferromagnetic with the Curie temperature reaching 300K [1].
ZnMnO layers were fabricated by thermal oxidation of nitrogen doped ZnMnTe films grown by MBE on GaAs and ZnTe substrates. In samples grown on GaAs, As is accumulated in the ZnO region as revealed by the SIMS analysis. Arsenic most probably, diffused from the GaAs substrate during the oxidation process. As a consequence samples were doped with both As and N acceptors. The Hall measurements demonstrated p-type conductivity with the high hole concentration. The XRD on ZnMnO samples present wurtzite polycrystalline character with metallic Te inclusion.
In photoluminescence spectrum from p-ZnMnO sample we observe an intensive peak located at 3.357eV, probably related to exciton bound to a neutral acceptor A0X or possible to an exciton bound to a neutral donor D0X is resolved.
Magnetooptical studies were performed in the Faraday configuration. PL peak dependence on the magnetic field shows an energy shift and a characteristic saturation. Magnetization measurements show a paramagnetic behavior and allow to evaluate the molar faction of Mn to be x=0.003, 0.0045 and 0.006. We fit the PL peak position vs. magnetic field using the Brillouin function and estimate the exchange constant No(α-β)=0.1eV. This extremely small value in II-VI DMS is discussed.
We acknowledge the support from the foundation for Polish Science through a Subsidy 8/2003. Part of the research was supported by the grant 1 P03B 084 30.
[1] T. Dietl, et al. Science, 287, 5455, pp. 1019-1022. (2000).

 

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Presentation: Poster at E-MRS Fall Meeting 2006, Symposium F, by Ewa Przezdziecka
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-16 14:53
Revised:   2009-06-07 00:44