Synthesis of advanced materials by pulsed-laser deposition

摘要

Advanced thin film materials with giant dielectric permittivities up to εr’ ≈ 10000 were produced by pulsed-laserrndeposition. Composite targets of barium titanate (BaTiO3) and polytetrafluorethylene (PTFE) were ablated with 248 nmrnKrF-laser radiation in Ar atmosphere. The synthesized films have a complex microstructure and contain product speciesrnwhich are formed during the pulsed-laser ablation / deposition process. The dielectric permittivities of films exhibitrnpronounced dispersion for frequencies higher than 10 kHz. Strong dependencies of the film permittivity on targetrncomposition, layer thickness, ambient gas pressure and relative humidity are revealed. The large dielectric permittivityrnof these film materials may be attributed to space-charge polarization phenomena. Films deposited from the samerntargets in oxygen atmosphere have much lower dielectric permittivity (εr’ ≈ 30).