偏振激光诱导的薄膜表面周期性自组织结构  

Polarized laser-induced self-assembled periodic structure on film surface

作　　者：于威[1] 卞雅兰[1] 张力[1] 郑炯[1] 

机构地区：[1]河北大学物理科学与技术学院,河北保定071002

出　　处：《光电子．激光》2010年第5期691-694,共4页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金资助项目(60878040);河北省自然科学基金资助项目(E2009000208)

摘　　要：本文研究了激光诱导的周期性表面结构(LIPSS)在聚甲基丙烯酸甲酯(PMMA)薄膜表面的形成过程。在导电玻璃衬底上制备得到PMMA薄膜,经p偏振的XeCl准分子激光照射后形成周期性的褶皱结构。用原子力显微镜(AFM)观察发现,形成的褶皱结构周期具有纳米量级,且当引入外加电场时,褶皱形成所需的激光脉冲数减少到2。当外加电压增加到30V时,褶皱的周期间隔明显减小,LIPSS变得不可控,出现了柱状的自组织结构。与直接用准分子激光照射的薄膜样品相比,外加辅助电压的引入改变了PMMA样品表面褶皱结构形成的时间和周期大小,褶皱形成的内部驱动力也发生了变化。The formation process of laser induced periodic surface structure（LIPSS） on polymethylmethacrylate（PMMA） is investigated.The PMMA film is prepared on an indium tin oxide wafer and irradiated with a p-polarized XeCl excimer laser （15 ns,308 nm）,assisted with an external electric field.The characteristics of the surface corrugations are determined by an atomic force microscopy.It is found that the corrugation spacing of nanometer scale can be achieved and remarkably decreased by changing the applied voltage from 5 V to 30 V.The applied electric field can decrease the laser pulse number for corrugation incubation and reduce the periodic spacing of the corrugations.The initial formation of periodic corrugations is attributed to the interference between the incident laser beam and its surface scattering wave.When high electric field is introduced,we find that the LIPSS becomes uncontrollable and pillars appear.The competition between surface tension and electrostatic force is considered to provide a positive feedback for a sinusoidal variation of the molten temperature.It is proposed that the main cause for the low controllability of the periodic corrugations is the non-phase matching between the driving force composed of surface tension and electrostatic force and the periodic temperature profile induced by laser irradiation.

关 键 词：激光诱导的周期性表面结构(LIPSS) 褶皱 聚甲基丙烯酸甲酯(PMMA) XECL准分子激光 形貌 

分 类 号：O484[理学—固体物理]