Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Strained superlattice from SVT GaAs P 1-x x, 0<x<0.36 (2.5 μm) p-type GaAs substrate GaAs (5 nm) GaAs (4 nm) GaAsP (3 nm) GaAs P (2.5 μm) 14 pairs Be doping

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Quantum Efficiency At bandgap: I ~ 6 muA/mW

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Polarization Pe ~ 80% at 780 nm

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Analyzing power SVT superlattice: A.P. ~ 3% Peak to peak A.P. Spire strained layer: A.P. ~ 10%

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Conclusions Polarization at least as high as S.L. P ~ 80% QE is 5 times higher than S.L.QE ~ 1% Analyzing power smallerA.P. ~ 3% Wafer treatment different, under study Sample loaded in tunnel failed Highs: Lows:

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy Thomas Jefferson National Accelerator Facility Polarization uniformity Uniform across a single chip