2004 Fiscal Year Final Research Report Summary
Studies on Heteroepitaxial Growth of III-V Diluted Magnetic Semiconductors on Si Substrates
| Project/Area Number |
14550005
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Nagaoka University of Technology |
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Principal Investigator |
UCHITOMI Naotaka Nagaoka University of Technology, Department of Electrical Engineering, Associate Prof., 工学部, 助教授 (20313562)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIKI Hisao Nagaoka University of Technology, Department of Electrical Engineering, Prof., 工学部, 教授 (50142237)
YAMAZAKI Makoto Nagaoka University of Technology, Department of Electrical Engineering, Prof., 教授 (90174474)
JINBO Yoshio Nagaoka University of Technology, Department of Electrical Engineering, Technical Staff, 工学部, 教務職員 (10134975)
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| Project Period (FY) |
2002 – 2004
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| Keywords | multi-step growth technique / heteroepitaxy / GaAs-on-Si / ferromagnetic transition temperature / anomalous Hall effect / III-V diluted magnetic semiconductors / low-temperature annealing / GaMnAs |
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| Research Abstract |
The III-V-based diluted magnetic semiconductor (Ga,Mn) As is one of the most promising materials for potential use in spintronic devices. (Ga,Mn) As is usually grown on GaAs substrates using low temperature molecular beam epitaxy (MBE), and has been combined with 4-6% Mn ions for metallic-phase ferromagnetism.
We investigated the growth of diluted magnetic semiconductor (DMS) (Ga_<1_x>, Mn_x) As epitaxial layers on n-type Si(100) substrates using low-temperature-molecular beam epitaxy (LT-MBE). The Mn content of the (Ga_<1_x>, Mn_x) As layers was relatively high (6.2%). The ferromagnetic transition temperature Tc was estimated to be 80 K for the as-grown film, and it strongly depended on the annealing temperature. The p-(Ga, Mn) As/n-Si heterostructures showing a ferromagnetic nature indicated a change in the sign of the Hall coefficient. We found that the transition temperature from n-type to p-type conduction considerably correlates with the Tc. We also studied the properties and annealing effects of substrate-free (Ga,Mn) As films prepared by etching Si substrates from (Ga,Mn) As/Si structures, and compared the results with those from (Ga,Mn) As/Si heterostructures. The substrate-free (Ga,Mn) As films with 6% Mn content were annealed at 250 degree C as a function of time. From Hall-effect measurements, the Curie temperature of substrate-free (Ga,Mn) As films was estimated to be 87 K for an as-grown film, enhanced up to 152 K after low temperature annealing for 60 min. We found that the (Ga,Mn) As films grown on Si substrates show a relatively high Curie temperature.
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