THE LUMINESCENCE OF LASI2-X FORMED BY ION-BEAM SYNTHESIS IN (111) SILICON-WAFER

The structure and luminescence of compound layer formed by 45-180 keV La ion implantation on (1 1 1) silicon substrate have been investigate d. X-ray diffractometer (XRD) was used to determine the phase structur e formed in ion beam synthesis. A fluorescence photospectrometer was u sed to measure the photoluminescence (PL). The results show that LaSi2 -x compounds have been formed directly during the ion implantation. Th e samples exhibited intensive luminescence and up-conversion luminesce nce at room temperature (RT). Their PL intensity decreased with increa sing of the excitation wavelength in the range from 120 to 250 nm. On the other hand, their PL intensity increases with increasing of the ex citation wavelength between 600 and 700 nm. The LaSi2-x films have bee n found to have a very high efficiency of up-conversion from red to bl ue-violet. (C) 1998 Elsevier Science B.V.