Highly photoconducting sillenite single crystals

摘要

Single crystals of Bi_(12)TiO_(20), and Bi_(40)Ga_2O_(63) (titanium, and gallium sillenite) were grown with use of Top Seeded Solution Growth (TSSG) technique. Mixed sillenites described by the formula Bi_(12)Ti_(1-x)M_xO_(20) (M=V, Ga, Pb), some of them doped additionally with Cu were also obtained. Photoconductivity under permanent, chopped, and pulse illumination and photochro-mism of obtained crystals were investigated and discussed. Some characteristic common features were found for photoconductivity obtained under conditions of chopped and constant illumination. Comparing the best known sillenite photoconductors we managed to obtain mixed titanium sillenites having photoconductivity four to five orders of magnitude higher.