Multilayers of GaAs/Mn deposited on a substrate of GaAs (001)

Abstract

In this work GaAs/Mn multilayers were deposited on GaAs (001) substrates by R.F magnetron sputtering technique, varying the deposition time (tg). Scanning electron and atomic force Microscopy studies were realized on the surface of the samples in order to determine the morphology and average roughness. X-ray diffraction spectra show that our samples tend to do amorphous. Raman spectroscopy at room temperature was employed to analyze the structural properties of the samples. We found that for a GaAs film taken as reference, the Raman spectra is dominated by the transverse (TO) and longitudinal (LO) modes located at 266 cm-1 and 291 cm-1, respectively. However, for the GaAs/Mn multilayers the TO and LO modes decrease dramatically, and the Mn Raman modes in the range of 100 cm-1 and 250 cm-1 are evidenced. Additional new peaks located around 650 and 690 cm -1 are only observed for the samples with high Mn content. By using the mass reduced model we estimate that the Mn related peaks are located at 650.2 cm-1 and 695.2 cm-1, in good agreement with the experimental data, these peaks are correlated with excitations due to (Mn)mAsn localized structures.