Search

Journal of applied physics 106, 083524 (2009). doi:10.1063/1.3246806, Published by American Institute of Physics, Melville, NY

We report the results of defect structures studies of silicon implanted at different temperatures with Mn ions (Si:Mn) and of GaMnAs layers, next annealed under ambient and high pressures. An influence of annealing conditions on structural properties of Si:Mn and GaMnAs layers was investigated. It has been confirmed that annealing of the Si:Mn samples after implantation results in crystallization of silicon inside the buried postimplanted layer, as well as in the formation of ferromagnetic Mn4Si7 precipitates. A change of strain in the GaMnAs layer, from the compressive to the tensile one, related to a creation of nanoclustered MnAs, was found to be dependent on processing conditions and primary existing structural defects, while independent of the Mn concentration. An influence of primary defects on the structural transformations of the GaMnAs layer is discussed. Приведено результати вивчення дефектних структур шарів кремнію, імплантованого іонами Mn (Si:Mn) при різних температурах, і GaMnAs з подальшим відпалом при зовнішньому і високому тиску. Досліджено вплив умов відпалу на структурні властивості шарів Si:Mn і GaMnAs. Показано, що відпал імплантованих зразків Si:Mn призводить до кристалізації кремнію усередині заглибленого постімплантованого шару, а також до утворення феромагнітних Mn4Si7-виділень. Виявлено, що зміна в GaMnAs-шарі напруження з того, що стискає, на те, що розтягує, пов'язана з утворенням нанокластерів MnAs, залежить від умов обробки і початкових дефектів структури і не залежить від концентрації Mn. Обговорюється вплив первинних дефектів на структурні перетворення в шарі GaMnAs.

4th MAG-EL-MAT Members Meeting 2006, Bellewo, POLAND, MAY 03-06, 2006; International audience; We report on the first studies of the optical properties of MBE-grown ZnTe nanowires (NWs). The growth of ZnTe NWs was based on the Au-catalyzed vapour-liquid-solid mechanism and was performed on (001), (011), or (111)B-oriented GaAs substrates. Investigated NWs have a zinc-blende structure, the average diameter of about 30 nm, and typical length between 1 and 2 mu m. Their growth axes are oriented along < 111 >-type directions of the substrate. The structural characterization of the NWs was performed by means of X-ray diffraction, using the synchrotron radiation corresponding to the wavelength of CuK(alpha 1) radiation W1 beamline at Hasylab DESY). The macro-Raman spectra of either as-grown NWs on GaAs substrate or of NWs removed from substrate and deposited onto Si were collected at temperatures from 15 K to 295 K using Ar(+) and Kr(+) laser lines. Strong enhancement of ZnTe-related LO-phonon structure was found for an excitation close to the exciton energy. Our studies revealed also the presence of small trigonal Te precipitates, typical of tellurium compounds.

Thin films of sphalerite-type ZnSe were grown by atomic layer deposition (ALD) from elemental Zn and Se precursors. These films, grown on various substrates, show bright blue 'edge' emission accompanied by donor-acceptor pair emissions in the blue, green and red spectral regions. Red, green and blue emissions mixed together give a white color, with a color temperature between 2400 and 4500 K depending on a layer thickness and temperature. ZnSe grown by ALD is in consequence a promising material for the fabrication of semiconductor-based white light emitting thin film electroluminescence displays. © 2003 Elsevier B.V. All rights reserved.

The effect of high hydrostatic pressure - high temperature treatment on strain state of thin GaAs layers, grown on vicinal (001) Si substrate, misoriented towards [110] with different miscut angles and with two different orientations of GaAs layer in relation to the miscut direction, was investigated by X-ray diffraction methods. The strain of the GaAs layers and GaAs/Si samples bending decreases when subjected to the treatment at T = 670 K under enhanced hydrostatic pressure (1.2 GPa). Dependence between the stress-induced structural changes and the orientation of GaAs miscut angle as well as peculiarities of the temperature-pressure treatment were determined. It has been shown that the amount of relaxed strain depends on the initial defect structure of the GaAs/Si hetrostructure. After reannealing the samples at higher temperature (870 K - 1.2 GPa), the strain and sample bending were the same as that after the treatment at 670 K - 1.2 GPa but the defect structure of layers was improved.