Dotierung von ZnO zur Herstellung von optoelektronischen Bauelementen im UV Spektralbereich
Zusammenfassung der Projektergebnisse
The primary goals of the project were optimization of the ZnO epitaxial growth employing molecular beam epitaxy, p-type doping of the ZnO layers and fabrication of light-emmiting structures on the base of the obtained layers. Thorough investigations of the MgO buffer layer formation and of the processes accomplishing it have been performed for the case of heteroepltaxial growth of ZnO on sapphire. The fonnation of spinel layer at the interface between AI2O3 and MgO have been found and further evaluated. Stress relief and formation of misfit dislocations are described. The influence of the growth parameters on the formation of ZnO layers has been investigated in detail. Special processing of ZnO bulk wafers has been developed and surfaces with atomic teraces were obtained. Both ZnO hetero- and homoepitaxial MBE growth was optimized concerning crystalline quality, layer morphology, and doping. Detailed investigations of nitrogen doping with subsequent annealing of ZnO layers have been carried out. A multilayer conductivity model for the analysis of the results of Hall measurements in such complicated epitaxial systems has been developed. High-quality ZnO/ZnMgO SQWs and MQWs as a part of the future optoelectronic devices have been demonstrated. We have also used ZnO/ZnMgO SLS in order to prevent dislocation propagation through the laer but TEM investigations showed that the SLS was not able to stop these defects. Alternative approaches are tested. Optically-pumped ZnO- and ZnO/ZnMgO-based lasers in cooperation with our partner from Switzerland have been successfully demonstrated. Till now no group worldwide has demonstrated reliable and reproducible p-type doping for the demonstration of efficient ZnO based LEDs. The p-type problem is still not solved.
Projektbezogene Publikationen (Auswahl)
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A two-step obtainment of quantum confinement In ZnO nanorods , Nanotechnology, 17, 2006, pp. 4859-4862
A C Mofor, A El-Shaer, M Suleiman, A Bakin and A Waag
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Photoluminescence properties: Catalyst-free ZnO nanorods and layers versus bulk ZnO, J. Appl. Phys. Lett. 89, 2006, 231911-231913
M. Al-Suleiman, A. C. Mofor, A. El-Shaer, A. S. Bakin, H.-H. Wehmann, and A. Waag
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Structural characterization of ZnO films grown by Molecular Beam Epitaxy on Sapphire with MgO buffer, J. Appl. Phys. 100,2006, 103506-103513
B. Pecz, A. El-Shaer, A. Bakin, A.-C. Mofor, J. Stoemenos and A. Waag
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Demonstration of an ultraviolet ZnO-based optically pumped 3rd order distributed feedback laser, Appl. Phys. Lett. 91, 2007, 111108
D. Hofstetter, Y. Bonetti. F. R. Giorgetta, A-H. El-Shaer, A. Bakin, A. Waag, R. Schmidt-Grund, M. Schubert, and M. Grundmann
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Etch-Pit Density Investigation on Both Polar Faces of ZnO Substrates, Electrochemical and Solld-State Letters, vol. 10, n. 12 2007
V. Petukhov, A. Bakin, A.-H. El-Shaer, A.-C. Mofor, and A. Waag
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Fabrication and characterization of n-ZnO on p-SiC heterojunction diodes on 4H-SIC substrates, J. Superiattices and Microstructures, Eisevier, Volume 42, Issues 1-6, 2007, pp. 387- 391
A. El-Shaer, A. Bakin, E. Schlenker, A. C. Mofor, G. Wagner, S. A. Reshanov and A. Waag
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Growrth kinetics and properties of ZnO/ZnMgO heterostructures grown by radical-source molecular beam epitaxy , Phys. Stat. Solidi (c) 4, No. 1, 2007, pp. 154-157
S.V. Ivanov, A. El-Shaer, T.V. Shubina, S.B. Listoshin, A. Bakin, and A. Waag
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Growth of wide band gap wurtzite ZnMgO epllayers on (0001) AI2O2 by radical-source molecular beam epitaxy , J. Superlattices and Microstructures, Elsevier, Volume 42, Issues 1-6, 2007, pp. 129-133
A. El-Shaer, A. Bakin, M. Al-Suleiman, S. Ivanov , A. Che Mofor, and A. Waag
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H202-Molecular Beam Epitaxy of high quality ZnO , Journal Applied Physics A: Materials Science and Processing, Springer 88, 2007, 57
A. El-Shaer, A. Bakin, A. Che Mofor, J. Bläsing, A. Krost, J. Stoimenos, B. Pecz, M. Kreye, A. Waag
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Layer by layer growth of ZnO on (0001) sapphire substrates by radical-source molecular beam epitaxy , J. Superlattices and Microstructures, Elsevier, Volume 42, Issues 1-6, 2007, pp. 158-164
A. Ei-Shaer, A. Bakin, A. Che Mofor, J. Stoimenos, B. Pecz, and A. Waag
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Misfit reduction by a Spinel layer formed during the epitaxial growth of ZnO on Sapphire using a MgO buffer layer, J. Crystal Growth, 308, 2007, pp. 314-320
A. Bakin, J. Kioseoglou , B. Pecz, A. El-Shaer, A.-C. Mofor, J. Stoemenos, A. Waag
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Optical Investigations and exciton localization in high qualltyZn. Mg 0-ZnO single quantum wells, Appl. Phys. Lett. 91,2007,081911
M. Al-Suleiman, A. El-Shaer, A. Bakin, H.-H.Wehmann and A.Waag
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Recombination dynamics and lasing in ZnMgO/ZnO single quantum well structures. Applied Phys. Lett. 91 (2007) 201104 (1-3)
T.V. Shubina, A.A. Toropov, O.G. Lublinskaya, S.B. Listoshin, A.A. Sitnikova, El-Shaer, M. Al- Suleiman, A. A. Bakin, A. Waag, E.V. Lutsenko, G.P. Yablonskii, J.P. Bergman, G Pozina, B. Monemar, S.V. Ivanov
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ZnMgO-ZnO Quantum Wells Embedded in ZnO Nanopillars: Towards Realisation of Nano-LEDs, Phys. Stat. Solidi (c), vol. 4, n l , 2007, pp. 158-16
A.Bakin, A. El-Shaer, A.C.Mofor, M. Al-Suleiman, E. Schlenker, and A.Waag
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Demonstration of a ZnO/MgZnO- based one-dimensional photonic crystal multlquantum well laser. Applied Physics Letters, 93 (10), (2008)101109
Hofstetter, D., Thron, R., El-Shaer, A.-H., Bakin, A., Waag, A.
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Molecular beam Epitaxy growth and Characterization of ZnO-based layers and heterostructures. Cuvillier Veriag Göttingen, 2008. Zugl.: (TU) Braunschweig, Univ., Diss., 2008; ISBN 978-3-86727-701-3,138 Seiten
Abdelhamid Abdelrehim Mahmoud Elshaer
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Structural and spectroscopic properties of a 2 inch ZnO-on-sapphire epiwafer grown by using molecular beam epitaxy. Journal of the Korean Physical Society, 53 (5 PART 2) (2008), pp. 2877-2879
Robin, l.C, Tavares, C , Rothman, J., Feuillet, G., El-Shaer, A.H., Bakin, A., Waag, A., Dang, L.S.
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Studies of N-doped p-ZnO layers grown on c-sapphire by radical source molecular beam epitaxy. Journal of the Korean Physical Society, 53 (5 PART 2), (2008)3016-3020
Ivanov, S.V., El-Shaer, A., Al-Suleiman, M., Bakin, A., Waag, A., Lyublinskaya, O.G., Shmidt, N.M., Listoshin, S.B., Kyutt, R.N., Ratnikov, V.V., Terentyev, A.Ya., Ber, B.Ya., Komissarova, T.A., Ryabova.L.l., Khokhlov, D.R.
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ZnO Nanostructures and Thin Layers for Device Applications. ECS Transactions, Volume 16(12) The Electrochemical Society (2008) 107
A. Bakin, A. Wagner, E. Schlenker, B. Postels, M. Al-Suleiman, A. Behrends, A.-H. Elshaer, V. Petukhov, A.Waag
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Compared optical properties of ZnO heteroepltaxial, homoepitaxlal 2D layers and nanowires. Journal of Crystal Growth, V. 311, (2009), iss. 7, pp. 2172-2175
Robin, I.e., Marotel, P., El-Shaer, A.H., Petukhov, V., Bakin, A., Waag, A., Lafossas, M., Garcia, J., Rosina, M., Ribeaud, A., Brechen, S., Ferret, P., Feuillet, G.
