1. 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 0.64 0.36 (2.5 μm) 14 pairs 5.10 19 5.10 17 5.10 18 Be doping

2. 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

3. 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

4. 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%

5. 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:

6. 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