Study of the composition transfer in the pulsed laser deposition of silicon substituted hydroxyapatite thin films

The field of biomaterials has lately been showing an important interest in the production of bioactive ceramic coatings capable of improving the adhesion of metal prostheses to the living tissue. Among these ceramics, the most notable is hydroxyapatite (HA) due to its similarities with the mineral part of the bone. The need to emphasize these resemblances led to the production of silicon substituted HA (Si-HA), a material which has shown better biological performance compared to the traditional HA. Coatings were prepared by pulsed laser deposition (PLD) technique, starting from mixtures of pure HA with Si powders. The laser–matter interaction successfully transferred the Si-HA to the substrate incorporating the Si atoms within its structure. The Si-HA thin films were characterized in terms of structure and chemical composition by many different techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XPS), energy dispersive spectroscopy (EDS) and ion beam spectroscopy techniques such as Rutherford back scattering (RBS), particle induced X-ray emission (PIXE), elastic recoil detection (ERD) and nuclear reaction analysis (NRA). The analysis demonstrated that Si is efficiently transferred to the HA structure in the form of SiO4 4 groups. The dependence of the target composition on the film growth and on the Si content of the coatings is also presented.