This however is not observed for the present study because the effective temperature of the ablated material is too high, and the strong positive ionisation of many of the particles would inhibit the formation of aggregates. Epigenetics Compound Library This is why only isolated particles are observed in the TEM micrograph of Figure 1b and others. Microparticles were not observed during the TEM analysis; however, the large abundance of nanoparticles indicate that the laser

parameters are well within the second threshold of ablation, i.e. only clusters and nanoparticles will be ablated. This is an ideal regime to work in for high-quality optical materials because of the expected decrease in surface roughness and a better continuity throughout the film. One could however expect some microparticles to become ablated over lengthy deposition times (e.g. 2 h or more) due to extensive surface modification of the target material [6]. Thin film deposition buy Poziotinib Silicon thin films were grown to investigate

microstructural quality and to determine whether they are suitable for optical applications and subsequent device fabrication. These were fabricated under the same laser parameters as used in the sub-monolayer find more analysis at 20 mTorr background gas pressure, where a greater abundance of silicon quantum dots are ablated. In order to assess the experimental parameters best suited for the fabrication of thin films, an array of samples was fabricated under varying conditions, and some of the conclusions identified are presented here. The primary variables analysed in this study are Fenbendazole the temperature of the substrate during the deposition, the laser fluence, the background pressure and the background gas type used. Presented in Figure 2 are SEM cross sections of selected thin films deposited under different parameters: (a) deposited at room temperature in Ar, (b) deposited at room temperature in 4%

H in Ar and (c) deposited at 200°C in 4% H in Ar. The cross sections of these samples were prepared by scouring the back of the silica substrates and then snapping along that line, taking adequate measures to ensure the film is not damaged in the process. This produces a clean break along the length of the sample where a cross section of the thin film can be seen clearly. From the presented images of Figure 2, it is clear that there is a considerable degree of variability in the density and morphology of the deposited films with regard to the deposition parameters. A key observation for the ablation of Si in either Ar or 4% H in Ar is that the addition of hydrogen to the argon gas considerably reduces the surface roughness and the appearance of cauliflower-like surface features (see Figure 2a).