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