TY - JOUR
T1 - Negative spin polarization observed by the Hanle effect in Al xGa1-xAs/GaAs quantum wells grown on processed surfaces
AU - Mejía-García, C.
AU - Winter, A.
AU - López-López, M.
AU - Gilinsky, A.
AU - Pascher, H.
N1 - Funding Information:
CM-G thanks the DAAD (Deutscher Akademischer Austauschdient) for the financial support on her 3 months in Germany. This work was partially supported by Conacyt-Mexico.
PY - 2010/10
Y1 - 2010/10
N2 - A series of quantum well (QW) structures of Al0.3Ga 0.7As/GaAs were characterized by photoluminescence spectroscopy with circularly polarized excitation at 1.6 K. The samples were grown by molecular beam epitaxy on a 500 nm thick GaAs buffer layer and contained three QW structures with thicknesses of 7, 5, and 3 nm, respectively. Four samples were prepared with different processing of the GaAs buffer layer surface (i: continuous growth, ii: in situ etching the GaAs buffer with Cl2 at 70 °C, iii: at 200 °C, respectively and iv: air-exposed buffer). The influence of buffer surface preparation on sample characteristics was analyzed. Using the Hanle effect the interband lifetime τ and the spin lifetime τs of the electrons were determined. A negative spin polarization was observed if the photon energy of the exciting light exceeds the difference between the spinorbit band and the conduction band. This inverse circular polarization could be related to the quality of the sample.
AB - A series of quantum well (QW) structures of Al0.3Ga 0.7As/GaAs were characterized by photoluminescence spectroscopy with circularly polarized excitation at 1.6 K. The samples were grown by molecular beam epitaxy on a 500 nm thick GaAs buffer layer and contained three QW structures with thicknesses of 7, 5, and 3 nm, respectively. Four samples were prepared with different processing of the GaAs buffer layer surface (i: continuous growth, ii: in situ etching the GaAs buffer with Cl2 at 70 °C, iii: at 200 °C, respectively and iv: air-exposed buffer). The influence of buffer surface preparation on sample characteristics was analyzed. Using the Hanle effect the interband lifetime τ and the spin lifetime τs of the electrons were determined. A negative spin polarization was observed if the photon energy of the exciting light exceeds the difference between the spinorbit band and the conduction band. This inverse circular polarization could be related to the quality of the sample.
KW - A. AlGaAs/GaAs
KW - B. Molecular beam epitaxy
KW - D. Hanle effect
KW - D. Spin polarization
UR - http://www.scopus.com/inward/record.url?scp=77955851801&partnerID=8YFLogxK
U2 - 10.1016/j.ssc.2010.07.027
DO - 10.1016/j.ssc.2010.07.027
M3 - Artículo
SN - 0038-1098
VL - 150
SP - 1746
EP - 1750
JO - Solid State Communications
JF - Solid State Communications
IS - 37-38
ER -