Spin injection with three terminal device based on (Ga,Mn)As/n GaAs-tunnel junction

We have fabricated a three terminal device integrating a (Ga,Mn)As Esaki diode and a light emitting diode (LED) to investigate the bias-voltage dependence of the injection of spin polarized electrons. The electroluminescence polarization (P_el) from the LED was measured under Faraday configuration as a function of bias voltages applied independently to the Esaki diode and to the LED. The polarization shows strong dependence on the bias applied to the Esaki diode when the LED bias is fixed. The maximum P _EL of 32.4% was observed when the valence electrons near the Fermi energy of (Ga,Mn)As are injected into the LED.