Influence Of Substrate-to-target Distance On The Properties Of Nc-Si Film Deposited By PLA

On the basis of the theory of deposition of Si films by pulsed laser, and supposing the atoms of ablated vapor and ambient gas may interact as elastic hard-sphere,the transport process of ablated vapor in the ambient gas has been successfully simulated by adopting Monte Carlo method in the work. Varying the substrate-to-target distance, the velocity distribution of those collision particles are taken into account. With increasing the substrate-to-target distance, we have found the average size of the Si nanoparticles first decreases and reaches its minimum at about 3cm, and then increases . And then we studied the influence of substrate-to-target distance on the properties of nc-Si film deposited in high purity gas of Ar. Nanocrystalline silicon films are prepared by pulsed laser ablation (PLA) on Si (111) and glass substrates. Several measuring techniques, including Scanning electronic microscopy (SEM), X-ray diffraction (XRD) and Raman Scattering spectroscopy (Raman), are used to analyze the morphology characteristic and component and microstructure of the nanocrystalline silicon films. The results indicate that the average size of the Si nanoparticles is controlled by adjusting the substrate-to-target distance; with increasing gas pressure, the average size of the nanoparticles first decreases and reaches its minimum (50nm) at 3cm, and then increases. A new theory is also proposed to search nucleation area through the root mean square of velocity which deduced from the temperature, and we provide some reference for the study of the vapor dynamic model of the Si films deposition by pulsed laser ablation.