Sol-gel derived structures for optical design and photocatalytic application

Scanning electron micrographs of (a and b) plane view of porous anodic alumina films grown on silicon: (a) without xerogel, (b) 7 xerogel layers of 30%Tb2O3 + 70%Al2O3 after annealing at 1000 °C for 30 min, (c) room-temperature luminescence under X-rays (radioluminescence) of this structure obtained with Cu Kα radiation energy 8.86 ke V, Ia = 15 mA with typical luminescence bands related to trivalent terbium.