Defects within the bulk of crystals were studied by using a specially designed microscopic fluorescence imaging system. The concentrations of the observed defect clusters varied; depending upon the crystal-growth method, the growth sector of the crystal and the rate of growth. The experimental method involved the acquisition of high-resolution fluorescence images of bulk defect cluster formations under continuous-wave 488nm photo-excitation. Annihilation/passivation of these defects was observed upon exposing the crystal to high-power 355nm laser irradiation.

Bulk Defect Formations in KH2PO4 Crystals Investigated using Fluorescence Microscopy. S.G.Demos, M.Staggs, H.B.Radousky: Physical Review B, 2003, 67[22], 224102 (6pp)