Optical and structural properties of GaSb-doped Mn based diluted magnetic semiconductor thin films grown via DC magnetron sputtering

Department of Physics, Group of Nanostructured Materials and their Applications, Universidad Nacional de, Colombia – Bogotá, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, 11001, Colombia

Adv. Mater. Lett., 2017, 8 (5), pp 650-655

DOI: 10.5185/amlett.2017.7110

Publication Date (Web): Apr 04, 2017

Copyright © IAAM-VBRI Press

E-mail: adussanc@unal.edu.co

Abstract

In this work, diluted magnetic semiconductor GaSb:Mn thin films were grown via DC magnetron Co-sputtering on glass substrates. The effect of synthesis parameters on the optical and structural properties was determined through spectral transmittance measurements and X-ray diffraction (XRD), respectively. Substrate temperature was changed from 373 to 523 K and layer thicknesses were obtained between 200 and 330 nm. All samples were subjected to annealing process to 623 K in situ. It was found that the optical constants (refractive index (n), absorption coefficient (a), extinction coefficient (k), and energy gap (E₁)) are significantly affected by the temperature and target power used during the synthesis process. In particular, a variation of the energy gap between 0.58 and 0.98 eV was obtained when the target power of GaSb varied between 80 and 140 W. GaSb, Mn₂Sb and SiO₂ phases were observed for lowest values of target power, where SiO₂ phase is a contribution of the substrate. The dielectric function of the compound with a dependence on synthesis parameters such as, the substrate temperature and deposition time was obtained, both real (e₁) and imaginary part (e₂). Analysis of the XRD measurements allowed to find that the (GaSb)Mn films grow with a mixture of the GaSb and Mn₂Sb phases, and an amorphous halo associated with the glass substrate. A correlation between synthesis parameters and optical properties is presented. Diluted magnetic semiconductors, like GaSb:Mn, are considered among promising materials for the development of new spin-electronic devices, high speed quantum-mechanical in computational information, other more; in this case, studies on magnetic properties in digital alloys of GaSb/Mn can be realized around of the optimization of Curie temperature.

Keywords

Diluted semiconductor, GaMnSb, sputtering method, spintronics.