TY - JOUR
T1 - Enhancement of Curie temperature in Ga1-xMnxAs epilayers grown on cross-hatched InyGa1-yAs buffer layers
AU - Maksimov, O.
AU - Sheu, B. L.
AU - Xiang, G.
AU - Keim, N.
AU - Schiffer, P.
AU - Samarth, N.
N1 - Funding Information:
We thank J. Van Vechten for motivating the experiments described in this manuscript. We are also grateful to Khalid Eid and Keh Chiang Ku for additional sample growth, and to M. S. Angelone for help with the XRD and EPMA measurements. Authors (O. M, G. X, and N. S) were supported by ONR Grants N00014-99-1-0071 and N00014-02-10996, and DARPA/ONR N00014-99-1-1093. Authors (B.L.S and P.S) were supported by DARPA N00014-00-1-0591 and NSF DMR-0101318. N.K. also acknowledges the support of the Penn State Physics REU site DMR-0097769.
PY - 2004/9/1
Y1 - 2004/9/1
N2 - Relaxed InyGa1-yAs epilayers grown on (001) GaAs are known to exhibit a cross-hatched surface with ridges running along the [110] and [11̄0] directions. We find that Ga1-xMnxAs epilayers grown on such buffer layers can have as-grown Curie temperatures (T C) that are higher than the as-grown 110K value typical of Ga 1-xMnxAs/GaAs heterostructures. Further, low-temperature annealing leads to only modest additional increases in TC, contrasting with the behavior in Ga1-xMnxAs/GaAs where TC typically increases significantly upon annealing. Our observations suggest that the initial concentration of Mn interstitials in as-grown Ga 1-xMnxAs /InyGa1-yAs heterostructures is smaller than that in as-grown Ga1-xMn xAs/GaAs heterostructures. We propose that strain-dependent diffusion may drive Mn interstitials from the bulk of the growing crystal to more benign locations on the ridged surface, providing a possible route towards defect-engineering in these materials.
AB - Relaxed InyGa1-yAs epilayers grown on (001) GaAs are known to exhibit a cross-hatched surface with ridges running along the [110] and [11̄0] directions. We find that Ga1-xMnxAs epilayers grown on such buffer layers can have as-grown Curie temperatures (T C) that are higher than the as-grown 110K value typical of Ga 1-xMnxAs/GaAs heterostructures. Further, low-temperature annealing leads to only modest additional increases in TC, contrasting with the behavior in Ga1-xMnxAs/GaAs where TC typically increases significantly upon annealing. Our observations suggest that the initial concentration of Mn interstitials in as-grown Ga 1-xMnxAs /InyGa1-yAs heterostructures is smaller than that in as-grown Ga1-xMn xAs/GaAs heterostructures. We propose that strain-dependent diffusion may drive Mn interstitials from the bulk of the growing crystal to more benign locations on the ridged surface, providing a possible route towards defect-engineering in these materials.
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U2 - 10.1016/j.jcrysgro.2004.05.091
DO - 10.1016/j.jcrysgro.2004.05.091
M3 - Article
AN - SCOPUS:4344680589
SN - 0022-0248
VL - 269
SP - 298
EP - 303
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 2-4
ER -