Effect of substrate orientation on magnetic properties of (Ga, Mn)As

Structural and magnetic properties of Ga0.93Mn0.07As layers grown on (001) and (311)A GaAs substrates by molecular-bean epitaxy are investigated. The as-grown (001) and (311)A Ga0.93Mn0.07As layers exhibit the same Curie temperature (TC) of 80K. However, upon annealing, the TC’s of the (001) and (311)A Ga0.93Mn0.07As layers are enhanced by 80 and 60K, respectively. X-ray diffraction studies reveal that the AsGa defects cannot be removed by low-temperature annealing, and a higher concentration of AsGa defects exist in the (311)A layers than in the (100) reference layers. The less enhancement in TC by annealing for the (311)A Ga0.93Mn0.07As layer can be ascribed to the larger amount of AsGa defects in the material.