Structural disordering and Refractive index measurements of B+ implanted Polycarbonate in the mid-infrared region

Structural modification and refractive index of PC specimens implanted with 50 keV B+ in the fluence range of 1x10(15)-5x10(16) ions cm(-2) have been analyzed in the mid-infrared wavelength region. The change in refractive index due to implantation has been studied by specular reflectance Fourier transform infrared spectroscopic technique. Structural modifications in implanted matrix have been observed by FTIR transmission and Raman Spectra. Formation of D and G bands with photo-luminescence (PL) background has been observed in the implanted specimens by Raman spectra recorded in 500-3500 cm(-1) range. A Raman shift has been observed in the position of D and G band with increasing ion fluence, which is attributed to the formation of hydrogenated amorphous carbon (HAC) structures. This observed dispersion in position and intensity ratio (ID/IG) of these bands with increasing ion fluence has been used to monitor carbon bonding in HAC structures. A continuous decline in crystallite size with increasing ion fluence has been observed; evidently supporting the increase in unorganized carbon in the graphitic layers formed in the implanted PC matrix. The possible correlation between the changes observed in refractive index and structural modification have been discussed. Such ion implanted PC polymer allows fabrication of optical waveguides and filters etc. in mid-infrared region.