Abstract
To prepare hydroxyapatite (Ca10(PO4)6(OH)2) thin films with a stoichiometric Ca/P ratio via pulsed laser deposition (PLD), the spot area of the laser pulse was changed independently of the laser fluence. To maintain a constant fluence when the spot area was changed, the total energy irradiated on the target surface was adjusted relative to the spot area. We found that the spot area dramatically changed the Ca/P ratio of the hydroxyapatite thin films that were prepared via PLD with a constant fluence. The best Ca/P ratio of 1.72 ± 0.13, which is close to the stoichiometric ratio (1.67), is achieved with a spot area and a fluence of 3.8 mm2 and 2.4 J/cm2, respectively. We report on the importance of the spot area in the PLD technique for the first time.
