Methods for spin injection managing in inGaAs/GaAs/Al2O3/CoPt spin light-emitting diodes

Circularly Polarized Electroluminescence of InGaAs/GaAs/CoPt Spin Light Emitting Diodes Placed in a Strong and Weak Magnetic Field

“…The semiconductor diode structure was formed by MOSVD at atmospheric hydrogen pressure [5,6]. The structure was three In x Ga 1−x As/GaAs quantum wells (QWs) of 10 nm width with different composition (0.1 < x < 0.25, to separate luminescence from each (QW) by wavelength) located at different distances from the surface (d s ).…”

“…The contact was a two-layer 8 nm CoPt/(1 nm Al 2 O 3 ), structure in which the magnetic CoPt layer is the source of spinpolarized carriers and the tunnel-thin Al 2 O 3 layer is necessary to enhance the spin injection efficiency. The method of production is described in detail in [5,6]. Injection nonmagnet Au/Al 2 O 3 -contacts were formed as reference ones.…”

“…The measurements were performed in a magnetic field up to 0.3 T at 10 K. The circular polarization of the recombination radiation from produced spin light-emitting diodes (SLEDs) and reference diodes with nonmagnetic contact were also studied in this paper. For this purpose, a forward constant bias was applied to the specimens, resulting in the excitation of electroluminescent radiation in the emission region of the InGaAs core (880−960 nm), which was recorded from the side of the GaAs [5,6] substrate transparent for this range. Specimens were introduced into an external perpendicular magnetic field to produce a circularly polarized radiation component.…”

“…In addition, a study of InGaAs/GaAs heterostructures with a ferromagnetic CoPt contact in [5] has shown that the circular polarization characteristics of electroluminescence were influenced by the magnetic field of the nonuniformly magnetized contact. The possibility of inverting the sign of the circularly polarized radiation due to the effect of precession of spin-polarized carriers in the transverse magnetic field of the CoPt contact was shown in the cited paper [5].…”

“…Under such conditions, the dynamics of radiative recombination is significantly influenced by the processes of spin relaxation of carriers to lower Zeeman levels. Analysis of these processes allows us to draw additional conclusions regarding the spin precession effect discussed in [5].…”