The Spatial Distribution Of Current Signal For Si Nanoparticles By Pulsed Laser Ablation

The process of pulsed laser ablation was monitored by a digital oscilloscope. In front ofthe target about1.5cm, a perforated panel was placed in order to obtain the ablation productswhich was moving along the axle of the target. Behind the baffle there is a plate electrodewhich is used to receive the ablation particles. The particles can generate electric currentwhich can be collected by the oscilloscope due to the charged particles. We have confirmedthat the meaning of current signal of each peak through analyzing the current signals underdifferent background gas pressures. The results indicate that the plate receives the highestnumber of nanometer silicon grains when the distance between the plate and target is2.5cm.With the increase of angle deviated from the target axis, the received number of nanometersilicon grains is decreasing. In order to verify the discipline of current signal, we haveintroduced a scattering field induced by a rod electrode to affect the process of ablation. Thinfilms are grown on the substrate placed on a semicircular quartz glass holder which is put infront of the target. We represent the characterization of the internal structure and morphologyof thin film by using X-ray diffractometer, scanning electron microscope (SEM) and Ramanscattering. The experimental results show that under the influence of scattering field theaverage size distribution of nanosilicon grain is broaden. After introduced the scattering field,we use MATLAB to make numerical simulation analysis, which is in accordance with theexperimental results. In this work, we put forward a new experimental method to test theablation process, which have provided the certain basis to control the average size ofnanosilicon crystal film.