Electrical spin injection into p-doped quantum dots through a tunnel   barrier
  We have demonstrated by electroluminescence the injection of spin polarized electrons through Co/Al2O3/GaAs tunnel barrier into p-doped InAs/GaAs quantum dots embedded in a PIN GaAs light emitting diode. The spin relaxation processes in the p-doped quantum dots are characterized independently by optical measurements (time and polarization resolved photoluminescence). The measured electroluminescence circular polarization is about 15 % at low temperature in a 2T magnetic field, leading to an estimation of the electrical spin injection yield of 35%. Moreover, this electroluminescence circular polarization is stable up to 70 K. 
L. Lombez, P. Renucci, P. Gallo, P. F. Braun, H. Carrere, P. H. Binh,   X. Marie, T. Amand, B. Urbaszek, J. L. Gauffier, T. ...