Relationship between the Ca/P ratio of hydroxyapatite thin films and the spatial energy distribution of the ablation laser in pulsed laser deposition

• Spot size of ablation laser changed Ca/P ratio of hydroxyapatite thin films in PLD.
• Difference of the composition between two spatial energy distributions was studied.
• Spatial uniformity of the laser energy is a key factor for stoichiometric thin films.

Variation of the Ca/P ratio in hydroxyapatite (Ca10(PO4)6(OH)2) thin films was studied in relation to the spot size of the ablation laser for two different spatial energy distributions in pulsed laser deposition. One energy distribution is the defocus method with a raw distribution and the other is the projection method without the weak portion at the edges of the ablation laser spot. A Ca/P ratio closer to that of stoichiometry was obtained with the larger spot sizes for both methods, and with the projection method compared to the defocus method. It is considered that a more uniform spatial energy distribution of the ablation laser improves the Ca/P ratio.

Figure optionsDownload as PowerPoint slide