Systematic investigation on the influence of the As-4 flux on the magnetic property of (In,Cr)As quantum dots

We study the structure, optical and magnetic characteristics of self-assembled (In,Cr) As diluted magnetic semiconductor quantum dots as a function of the As-4 flux. Increasing the surface energy by increasing the As4 pressure leads to a smaller number of larger dots for a higher As-4 flux. The remanent magnetization measured at 5K also increases with increasing As-4 flux, which is attributed to the enhancement of the effective Cr content due to the As-4-rich condition. We explore the possibility of tailoring magnetism by controlling the As-4/In flux ratio without changing the Cr concentration. Furthermore, extremely low-density QDs have also been successfully grown. Copyright (C) EPLA, 2008

National Natural Science Foundation of China 10674130 107103156083600260521001Major State Basic Research of China 2007CB924903 Chinese Academy of Sciences KJCX2.YW.W09-1 The authors acknowledge Y. H. Zheng, L. Chen, P. F. Xu for their help with the sample preparation, H. Y. Zhang for SQUID measurements and Z. Y. Cheng for TEM measurements. This work was supported partly by the National Natural Science Foundation of China under Grant Nos. 10674130, 10710315, 60836002, 60521001, by the special funds for the Major State Basic Research Contract No. 2007CB924903 of China, and by the Knowledge Innovation Program Project of the Chinese Academy of Sciences No. KJCX2.YW.W09-1.