Intrinsic defect-related blue-violet and ultraviolet photoluminescence from Si+-implanted fused silica

Photoluminescence (PL) and electron-spin resonance have been used to study intrinsic defects in fused silica during ion implantation and annealing pro cedures designed to form and H-passivate Si crystallites. Under 250 nm (5 e V) photon excitation, the unimplanted silica has PL bands at 390 (3.2 eV) a nd 288 nm (4.3 eV). Implantation with 400 keV Si ions creates paramagnetic defects but reduces both the 3.2 and 4.3 eV emissions. Implantation to dose s greater than or equal to 2 x 10(17) Si cm(-2) produces an additional weak emission band at 466 nm (2.7 eV). Annealing at 1000 degrees C and hydrogen ation at 500 degrees C affect both the absolute and relative intensities of the 390 and 288 nm emissions, and this is discussed with reference to know n defects in the Si-crystallite/silica system. However, the emissions remai n weak compared to those in unimplanted silica even though annealing remove s the paramagnetic defects produced by implantation and the weak 466 nm emi ssion observed for high doses. Since no other emission is evident at lower energies, it is concluded that implantation either alters or destroys the d efect configurations responsible for the 390 and 288 nm emissions or that i t creates diamagnetic defects which offer competing nonradiative relaxation channels. (C) 2000 American Institute of Physics. [S0003-6951(00)00515-5].