Metallic films forming on the surface of alkali-halide crystals during thermal diffusion of intracrystalline immpurities

Enhanced photo-response of thin-film structures with nanocrystals

“…Ion implantation [17], thermal treatments [18] and ionising radiation bombardment (combined with special annealing [15,16,19,20]) are established tools for metal nanoparticles formation in solids. Understanding the structural evolution during the preparation of nanocomposites can be of great help in understanding how to control the characteristics of the final products.…”

“…Clusters of F-CCs (lithium colloids) and impurity colloids can be created in LiF at temperatures where diffusion of point defects and impurities is possible [18][19][20]. Even though the actual mechanism of the formation of such colloids is still an open question, a lot of attention was devoted to study the optical properties of the crystals (nanocrystals) containing these metallic aggregates.…”

“…Unfortunately, not only bulk, but boundary (surface) states of nanocrystals affect strongly their physical properties as their size reduces [14]. The properties of thin layers and nanocrystals as prepared and post-growth processed by different methods can be affected by the presence of impurities, crystal defects and aggregation of impurities and intrinsic defects to the colloids in the bulk and surface regions [13,[15][16][17][18][19][20] related to the used preparation technique.…”

Optical properties of coloured LiF crystals with given content of oxygen, hydroxyl and metal impurities

“…1 Introduction Because of its importance for basic and applied research [1,2], lithium fluoride (LiF) has been investigated in connection with colour centres (CCs), but very often various authors use crystals grown and coloured by different methods, and the results obtained by them are affected by "technological" impurities [3,4], and crystal bulk and surface defects [3,[5][6][7]. If the colouring is carried out by irradiation with X-or γ-rays, then uniform concentration of CCs throughout the sample is produced.…”

“…1b. The absorption is due to metal ions [7][8][9], while the emission is due to both oxygen [10] and ion impurities. The latter ones are evidenced in the bleached LiF-3 by optical losses due to absorption (excitation) at 216, 240 nm and reflection at 307 nm, as well as by emission at 380-430 nm after excitation at λ exc = 216 nm, see Fig.1c.…”