Segregation of Mn into GaAsMn thin films prepared by magnetron sputtering

ABSTRACT

Currently, the manufacture of thin films of GaAs doped with Mn (GaAsMn) on Si (100), is an object of great interest, due to its possible integration with silicon technology, generating a significant development in the functionality of the devices optoelectronics and spintronics. In this work, we present a systematic study of the structural, optical, morphological and magnetic characterization of GaAsMn thin films prepared by R.F sputtering on a Si (100) substrate, for growth temperatures of 100 and 200 oC, respectively. From Raman spectra, the transverse optical (TO) and longitudinal optical (LO) vibrational modes, located at 290 cm^-1 and 265 cm^-1 of GaAs were identified. Additionally, vibrational modes of MnAs were identified, due to the replacement of Ga atoms with Mn atoms in high concentrations. The segregation of Mn was bear out by X-ray diffraction, where crystalline planes are evidenced in the directions (400) and (200) of polycrystalline GaAs, and crystallographic planes belonging to the Mn_1+xAs phases. The morphology and growth mode of the thin films of GaAsMn / Si (100), was carried out by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM) images, taken on the surface and in cross-section, respectively. Finally, an analysis of the magnetic properties of the GaAs thin films made from magnetic force microscopy (MFM) images, evidence surface magnetic domains formation, which depending on growth conditions. We concluded that, all properties of GaAsMn thin films are depending on growth conditions.

Keywords
Magnetron Sputtering r.f,; Diluted Magnetic Semiconductors; GaAsMn