12 research outputs found
Analysis of the Electronic and Band-Structure in As-grown and Annealed (Ga,Mn)As Epitaxial Layers
The photoreflectance (PR) spectroscopy was applied to study the band-structure evolution in
(Ga,Mn)As layers with increasing Mn content. We investigated (Ga,Mn)As layers and, as a reference, undoped
GaAs layer, grown by LT-MBE on semi-insulating (001) GaAs substrates. Photoreflectance studies
were supported by Raman spectroscopy and high resolution X-ray diffractometry (XRD) measurements.
Magnetic properties of the (Ga,Mn)As films were characterized with a superconducting quantum interference
device (SQUID) magnetometer. In addition, we investigated impact of the annealing of 100 nm
(Ga,Mn)As layers with 6% of the Mn content on the electronic and band structure as well as on the electrical
and magnetic properties of these films. Our findings were interpreted in terms of the model, which assumes
that the mobile holes residing in the valence band of GaAs and the Fermi level position determined
by the concentration of valence-band holes.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3499
Band-structure analysis in (Ga,Mn)As epitaxial layers
The ternary III-V semiconductor (Ga,Mn)As has recently drawn a lot of attention as the model diluted ferromagnetic semiconductor, combining semiconducting properties
with magnetism. (Ga,Mn)As layers are usually gown by the low-temperature molecular-beam epitaxy (LT-MBE) technique. Below a magnetic transition temperature, TC, substitutional Mn2+ ions are ferromagnetically ordered owing to interaction with
spin-polarized holes. However, the character of electronic states near the Fermi energy and the valence-band structure in ferromagnetic (Ga,Mn)As are still a matter of controversy.
The photoreflectance (PR) spectroscopy was applied to study the band-structure evolution in (Ga,Mn)As layers with increasing Mn content. We have investigated thick (800 - 700nm and 230 – 300nm) (Ga,Mn)As layers with Mn content in the range from
0.001% to 6% and, as a reference, undoped GaAs layer, grown by LT-MBE on semiinsulating (001) GaAs substrates. Our findings were interpreted in terms of the model, which assumes that the mobile holes residing in the valence band of ferromagnetic
(Ga,Mn)As and the Fermi level position determined by the concentration of valenceband holes.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2063
Neel temperature of zinc-blende, MBE-grown MnTe layers: modification by the crystal growth conditions
International audienceWe present evidence of the influence of the substrate (GaAs and CdZnTe) on the magnetic properties and on the surface structure of (001) zinc-blende MnTe grown by molecular beam epitaxy. High-resolution X-ray diffraction and atomic force microscopy were employed in the characterisation of the MnTe structure. The temperature dependence of collective spin excitations (magnons) was determined via Raman scattering and subsequently analysed in order to study selected magnetic properties. Differences in both the Néel temperature and magneto-elastic coupling between the MnTe layer and the given substrate were demonstrated, and mechanisms contributing to these effects are discussed