Analysis of Raman scattering of Ga1-xMnxAs dilute magnetic semiconductor

Ferromagnetic Ga1-xMnxAs layers (where x = 1.4-3.0%) grown on (100) GaAs substrates by molecular beam epitaxy were characterized using Raman spectroscopy. As Mn is introduced into GaAs, a marked increase in disorder in the material occurs, as indicated by the growth of the disorder-allowed transverse-optical Raman line. Another important result is that as the Mn concentration in Ga1-xMnxAs increases further beyond ca. 2%, Raman-active coupled-plasmon-longitudinal-optical phonon modes arise, which signals the increasing presence of holes, and thus provides a useful tool for determining their concentration. Using the depletion-layer approach from the Raman spectroscopy data, we determined the carrier concentration for samples with x = 2.2% and 3.0% was to be 7.2 x 10(19) and 8.3 x 10(20) cm(-3), respectively. (c) 2009 Elsevier B.V. All rights reserved.