Dynamics of plume propagation and splitting during pulsed-laser ablation of Si in He and Ar
Dynamics of plume propagation and splitting during pulsed-laser ablation of Si in He and Ar
复制标题
DOI：
10.1103/physrevb.58.1533
复制
发表时间：
1998
影响因子：
3.7
通讯作者：
R. F. Wood;J. Leboeuf;D. Geohegan;A. Puretzky;Kuan-Ren Chen
中科院分区：
文献类型：
--
作者：
R. F. Wood;J. Leboeuf;D. Geohegan;A. Puretzky;Kuan-Ren Chen
提出了一种计算激光等离子体向背景气体中膨胀的模型方法。虽然相对简单的结构，该模型给出了良好的适合各种实验数据的Si在背景气体的He和Ar，包括以前无法解释的{open_quotes}分裂{close_quotes}的烧蚀羽。该模型是基于多重散射和流体动力学方法的组合。它允许羽流被分解成组分或散射级，其粒子与背景发生0，1，2，{hor_ellipssis}碰撞。粒子只能通过碰撞从一阶转移到下一个更高阶。各个阶的密度根据通常的守恒方程传播，以给出总体羽流膨胀。当Ar是背景气体时，Si羽流原子将在不经历任何碰撞的情况下到达检测器的概率是不可忽略的。这导致除了来自散射通量的延迟峰值之外，通量分量与当不存在背景气体时获得的通量分量相比未被移位。在Ar中，只有几个订单是必要的收敛。轻气体He中的行为更复杂，因为任何一个散射事件的影响相对较小，并且在某些情况下必须进行高达第12散射阶的计算以找到与实验的一致性。{copyright} {ital 1998} {ital The American Physical Society}«收起
A modeling approach for calculating the expansion of a laser-generated plasma into a background gas has been developed. Although relatively simple in structure, the model gives excellent fits to various experimental data for Si in background gases of He and Ar, including the previously unexplained {open_quotes}splitting{close_quotes} of the ablated plume. The model is based on a combination of multiple-scattering and hydrodynamic approaches. It allows the plume to be broken up into components, or scattering orders, whose particles undergo 0, 1, 2,{hor_ellipsis} collisions with the background. Particles can only be transferred from one order to the next higher order by collisions. The densities in the individual orders propagate according to the usual conservation equations to give the overall plume expansion. When Ar is the background gas, there is a non-negligible probability that Si plume atoms will reach the detector without undergoing any collisions. This gives rise to a flux component that is undisplaced from that obtained when no background gas is present in addition to the delayed peak from the scattered flux. In Ar only a few orders are necessary for convergence. The behavior in the light gas He is more complex because of the relatively small effect of any one-scatteringmore » event and the calculations must be carried out in some cases to as high as the 12th scattering order to find agreement with the experiments. {copyright} {ital 1998} {ital The American Physical Society}« less