Study Of Nuclear And Charge Of Si Nanocrystalline Deposited By Pulsed Laser Ablation

In this article the puls laser depsition is applied. Combining hydrodynamic model andnucleation area model, the effect of ambient air pressure and parallel mask on themicroscopic process of collision of ablated particles with ambient gas atoms, nucleation andtransmission is experimental studied. In different conditions of ambient pressure and maskposition, the location and region of nucleation area of Si nanoparticles are analysis confirmed.Furthermore, this partiles try to reveal the mechanism of pulse laser ablation and explore thekey factor of impacting the nucleation size through research the charging characteristics ofthe laser ablation particles by measuring the current response of the ablated particles. Thiswork will contribute to in-depth understanding Si nanoparticles nucleation mechanismof oflaser ablation dynamic process and the preparation of high quality Si nanoparticles. Themain results are as follows:1. In order to investigate the effect of the ambient pressure on the nucleation area rangeof Si nanoparticles, the single crystalline Si target with high resistivity was ablated by aXeCl excimer laser, and in the ambient pressure range from1to200Pa of pure Ar gas. TheSi nanocrystalline films were systemically deposited on a glass or single crystalline Sisubstrate lined up at a distance of2.0cm under the plasma. The results show that with theincreasing of ambient pressure, the range of Si nanoparticles into the nucleus begins toincrease, up to a maximum of3.63cm in pressure of50Pa; the range of the nucleation zonebegan to decrease slowly when continuing to raise the air pressure.2. In10Pa ambient pressure of Ar, the mask away from the target is vertical placed andthe Si nanocrystalline films were systemically deposited on the substrate lined up horizontaldirection under the plasma. The effect of mask position on nucleation area characteristicparameters (the range of the nucleation zone, width, etc.) of Si nanoparticles by puls laserablation is studied. The results show that nucleation area range of Si nanoparticles with theincrease of the distance of the bezel, when the mask placed3cm from the target nucleationarea range of Si nanoparticles reaches a minimum value of2.78cm. Nucleation area rangeof Si nanoparticles reaches a maximum value without mask.3. In order to obtain the the ablated particles of approximately horizontal directiontransmission, the mask with a hole in the center is placed between the target and the substrate. By changing the size of the hole in the mask, the effect of diameter of the hole onthe Si nanoparticles production and distribution by laser ablation deposition is quantitativestudied. It is obtained that with the gradually decreasing of the aperture size the average sizeof Si nanoparticles, the quantity of Si nanoparticles is proportional to the power of1.5of thehole diameter.4. The charging characteristics of the laser ablation particles under different pressureare systematic investigated by measuring the current response of ablation particles on thebasis of the above study. The results show that the concentration of silicon ions in theablated particles presented first increases and then decreases trends with the increasing ofambient pressure, The concentration of silicon ions reaches a maximum in the gas pressureof3Pa; The numbers of Si nanopaticles with a positive charge, under the ambient pressureof8Pa conditions, reaches to the maximum. In addition, the speed and damping coefficientof the silicon ions is invested by using this method, and concluded that they have anon-linear relationship with the ambient pressure.