M. I. Lukasiewicz

Publications (5)4.76 Total impact

• Source

  Available from: Rafał Jakieła

  Article: Synchrotron photoemission study of (Zn,Co)O films with uniform Co distribution

  E Guziewicz, M I Lukasiewicz, L Wachnicki, K Kopalko, A Ková Cs, R E Dunin-Borkowski, B S Witkowski, B J Kowalski, J Sadowski, M Sawicki, R Jakiela, M Godlewski
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  ABSTRACT: a b s t r a c t We present results of a resonant photoemission study of (Zn,Co)O films with Co content between 2% and 7%. The films were grown by Atomic Layer Deposition (ALD) at low temperature of 160 1C, and show fully paramagnetic behavior. The Co ions are uniformly distributed in the ZnO matrix and are free of foreign phases and metal accumulations as indicated by TEM data. The electronic structure of (Zn,Co)O films was studied by Resonant Photoemission Spectroscopy across the Co3p–Co3d photo-ionization threshold. We have observed that the resonant enhancement of the photoemission intensity from the Co3d shell is not the same for samples with different cobalt content. We suggest that the Co3d contribution to the valence band depends on both Co and H content.
  Journal of Crystal Growth 02/2013; 320:1. · 1.73 Impact Factor
• Source

  Available from: Janusz W. Sobczak

  Article: Homogenous and heterogeneous magnetism in (Zn,Co)O

  M. Sawicki, E. Guziewicz, M. I. Lukasiewicz, O. Proselkov, I. A. Kowalik, W. Lisowski, P. Dluzewski, A. Wittlin, M. Jaworski, A. Wolska, [......], M. T. Klepka, F. J. Luque, D. Arvanitis, J. W. Sobczak, M. Krawczyk, A. Jablonski, W. Stefanowicz, D. Sztenkiel, M. Godlewski, T. Dietl
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  ABSTRACT: A series of (ZnO)m(CoO)n digital alloys and superlattices grown by atomic layer deposition has been investigated by a range of experimental methods. The data provide evidences that the Co interdiffusion in the digital alloy structures is sufficient to produce truly random Zn1-xCoxO mixed crystals with x up to 40%. Conversely, in the superlattice structures the interdiffusion is not strong enough to homogenize the Co content along the growth direction results in the formation of (Zn,Co)O films with spatially modulated Co concentrations. All structures deposited at 160\circC show magnetic properties specific to dilute magnetic semiconductors with localized spins S = 3/2 coupled by strong but short range antiferromagnetic interactions that lead to low temperature spin-glass freezing. It is demonstrated that ferromagnetic-like features, visible exclusively in layers grown at 200\circC and above, are associated with an interfacial mesh of metallic Co granules residing between the substrate and the (Zn,Co)O layer. This explains why the magnitude of ferromagnetic signal is virtually independent of the film thickness as well as elucidates the origin of magnetic anisotropy. Our conclusions have been derived for layers in which the Co concentration, distribution, and aggregation have been determined by: secondary-ion mass spectroscopy, electron probe micro-analysis, high-resolution transmission electron microscopy with capabilities allowing for chemical analysis; x-ray absorption near-edge structure; extended x-ray absorption fine-structure; x-ray photoemission spectroscopy, and x-ray circular magnetic dichroism. Macroscopic properties of these layers have been investigated by superconducting quantum interference device magnetometery and microwave dielectric losses allowing to confirm the important role of metallic inclusions.
  01/2012;
• Source

  Available from: Rafał Jakieła

  Article: ZnCoO Films by Atomic Layer Deposition - influence of a growth temperature on uniformity of cobalt distribution

  M. I. Lukasiewicz, B. Witkowski, M. Godlewski, E. Guziewicz, M. Sawicki, W. Paszkowicz, E. Lusakowska, R. Jakiela, T. Krajewski, I.A. Kowalik, B.J. Kowalski
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  ABSTRACT: We report on the structural, electrical and magnetic properties of ZnCoO thin films grown by Atomic Layer Deposition (ALD) method using reactive organic precursors of zinc and cobalt. As a zinc precursor we applied either dimethylzinc or diethylzinc and cobalt (II) acetyloacetonate as a cobalt precursor. The use of these precursors allowed us the significant reduction of a growth temperature to 300oC and below, which proved to be very important for the growth of uniform films of ZnCoO. Structural, electrical and magnetic properties of the obtained ZnCoO layers will be discussed based on the results of SIMS, SEM, EDS, XRD, AFM, Hall effect and SQUID investigations.
  07/2011;
• Source

  Available from: Rafał Jakieła

  Article: Electrical parameters of ZnO films and ZnO-based junctions obtained by atomic layer deposition

  T A Krajewski, G Luka, L Wachnicki, A J Zakrzewski, B S Witkowski, M I Lukasiewicz, P Kruszewski, E Lusakowska, R Jakiela, M Godlewski, E Guziewicz
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  ABSTRACT: This work reports on the zinc oxide layers grown by atomic layer deposition (ALD) from dimethylzinc (Zn(CH3)2, DMZn) or diethylzinc (Zn(C2H5)2, DEZn) and deionized water precursors. These films are suitable for nanoelectronic applications, e.g. selecting elements in the new generation of non-volatile 3D memories constructed in the cross-bar architecture. This architecture imposes strict requirements on the parameters of obtained ZnO layers. Growth temperature must be below 200 °C, electron concentration not higher than 1017 cm−3 and mobility above 10 cm2 V−1 s−1. This is possible when the ALD growth method is used. We demonstrate the correlations between the structural, optical and electrical properties of ALD-ZnO layers. Their control allows us to obtain Schottky junctions with silver, whose parameters are suitable for the applications mentioned above. The ideality factor of about η ≈ 2.65 was calculated for the Schottky diodes based on the pure thermionic emission theory.
  Semiconductor Science and Technology 05/2011; 26(8):085013. · 1.72 Impact Factor
• Source

  Available from: Rafał Jakieła

  Article: Role of interface in ferromagnetism of (Zn,Co)O films

  M. Godlewski, E. Guziewicz, M. I. Lukasiewicz, I.A. Kowalik, M. Sawicki, B. S. Witkowski, R. Jakiela, W. Lisowski, J. W. Sobczak, M. Krawczyk
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  ABSTRACT: We demonstrate that room temperature ferromagnetic response (RT FR) of ZnCoO films grown at low temperature by the Atomic layer Deposition (ALD) method is due to Co metal accumulations at the ZnCoO/substrate interface region. The accumulated experimental evi evidences allow us to reject several other explanations of this effect in our samples, despite the fact that some of them are likely to be responsible for the low temperature FM in this class of the material.
  physica status solidi (b) 01/2011; 248:1596-1600. · 1.32 Impact Factor