Growth and properties of (Ga,Mn)As films with high Mn concentration

(Ga, Mn)As films with high nominal Mn concentration (0 <x <0.55) are grown by low temperature molecular beam epitaxy (LT-MBE), growth temperature T-s = 180 degreesC. Reflection high energy electron diffraction patterns indica te epitaxial growth of (Ga, Mn)As for x <0.1, whereas they show spotty patt erns for x >0.1, which turn to polycrystalline features when x >0.3. X-ray diffraction shows the formation of MnAs together with the growth of (Ga, Mn )As. The lattice constant of the layers suggests that (Ga, Mn)As with high Mn composition as high as 17% can be grown by LT-MBE. (C) 2001 American Ins titute of Physics.