Figure 8: PL images of samples after illuminated annealing. Top wafers (a, c, and e) were as deposited with no prefiring process. Bottom wafers (b, d, and f) were prefired at 973 K in belt furnace to activate hydrogen and distribute it throughout the bulk. First column wafers (a and b) were illuminated with the photon flux of 1.2 × 1017 photons/cm2/s. Second column wafers (c and d) were illuminated with 9 × 1017 photons/cm2/s. And third column wafers (e and f) were illuminated with 1.7 × 1018 photons/cm2/s. For each sample, the left half of the sample was heated on the hot plate, while the right half was off the hot plate.