Effect of pulsed laser annealing on the properties of (Ga,Mn)As layers

Abstract

• Ferromagnetic (Ga,Mn)As layers were obtained by pulsed laser deposition and annealing. • Results of X-ray diffraction, TEM and the magnetization study are presented. • Decomposition of MnAs inclusions is observed after laser annealing of thin (Ga,Mn)As layer. • The Curie temperature increased to 105–110 K in the annealed thin (Ga,Mn)As layer. We have investigated the layers of the (Ga,Mn)As diluted magnetic semiconductor with the thickness in the range of 150 – 400 nm, which have been formed by the combination of the methods of a pulsed laser deposition and a post-growth pulsed laser annealing. It has been found that the laser annealing has a significant effect on the structural, magnetic, and electrical properties of the thinnest (∼150 nm) (Ga,Mn)As layer. For this layer the additional activation of the Mn impurity, the Curie temperature increase and the dissolution of the second phase MnAs clusters have been observed. The results of model calculations of heat spread in (Ga,Mn)As layer have shown that in thicker layers a MnAs melting point temperature is not achievable (for the chosen conditions of pulsed laser annealing) in the entire layer.