Size and Strain Analysis of CaF2 Thin Films.

CaF2 thin films of three different thicknesses 50nm, 100nm and 150nm have been deposited on three different substrates Si, Al and glass by electron beam evaporation technique and have been irradiated by 100 MeV Au+9 ions. Average grain size in each film has been calculated by using Debye Scherrer's formula and strain has been calculated using Williamson-Hall plot (W-H plot) method. Increase in grain size and decrease in lattice strain has been observed with increase in film thickness. Also, grain size and strain are found to have different values for different substrates while thickness of the film is same. Grain size has also been found to decrease with ion fluence which is attributed to strain induced fragmentation of grains. [ABSTRACT FROM AUTHOR]