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Title: Room temperature spin injection into (110) GaAs quantum wells using Fe/x-AlO{sub x} contacts in the regime of current density comparable to laser oscillation

We investigate the electrical spin injection into (110) GaAs single quantum wells (SQWs) and multiple quantum wells (MQWs) using light-emitting diodes (LEDs) having Fe/crystalline-AlO{sub x} (x-AlO{sub x}) tunnel barrier contacts. A degree of circular polarization (P{sub c}) of 5.0% is obtained for the SQW LED at 4 K with the current density of 1 kA/cm{sup 2} which is comparable to that for the laser oscillation in vertical-cavity surface-emitting lasers (VCSELs). On the basis of electron spin relaxation time and carrier lifetime in the (110) GaAs SQW measured by time-dependent photoluminescence and the value of P{sub c} = 5.0%, the degree of spin polarization of initially injected electrons (P{sub 0}) in the SQW is estimated to be 6.6% at 4 K. By using the MQW LED having a much stronger electroluminescence, a P{sub c} value of 2.6% is obtained at room temperature (RT) with the current density of 1.5 kA/cm{sup 2}. The temperature and current density dependences of P{sub c} are found to be weak in both the SQW and MQW LEDs. The estimated P{sub 0} of 9.3% at RT suggests that the Fe/x-AlO{sub x} contacts can be used for the RT electrical spin injection for spin-controlled VCSELs.
Authors:
; ; ;  [1] ; ;  [2]
  1. Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)
  2. Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259-J3-15 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)
Publication Date:
OSTI Identifier:
22492850
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARRIER LIFETIME; CURRENT DENSITY; ELECTROLUMINESCENCE; GALLIUM ARSENIDES; LASERS; LIGHT EMITTING DIODES; OSCILLATIONS; PHOTOLUMINESCENCE; POLARIZATION; QUANTUM WELLS; SPIN; TEMPERATURE RANGE 0273-0400 K