Optical detection of hot-electron spin injection into GaAs from a magnetic tunnel transistor source

Injection of spin-polarized hot-electron current from a magnetic tunnel transistor into GaAs is demonstrated by the observation of polarized light emission from a GaAs/In0.2Ga0.8As multiple quantum well light-emitting diode. Electroluminescence from the quantum wells shows a polarization of similar to10% after subtraction of a linear background polarization. The polarization shows a strong dependence on the bias voltage across the diode, which may originate from changes in the electron spin relaxation rate in the quantum wells under varying bias conditions.