Pulsed laser deposition of nanoparticle films of Au

Nanosecond pulsed laser deposition (PLD) has been used to grow nanoparticle films of Au on Si and sapphire substrates. The equivalent solid density thickness was measured with a quartz crystal monitor and the ion flux was measured with a time-of-flight Langmuir probe. The ion signal yields the ion energy distribution. The angular distribution of deposited material and the ablated mass per pulse were also measured. These values are incorporated into an isentropic plasma expansion model for a better description of the expansion of the ablated material. Atomic force microscopy and UV/vis optical spectroscopy were used to characterise the films. Atomic force microscopy shows that in the equivalent thickness range 0.5–5 nm the deposited material is nanostructured and the surface coverage increases with increasing equivalent thickness. The optical absorption spectra show the expected surface plasmon resonance, which shifts to longer wavelengths and increases in magnitude as the equivalent thickness is increased.