Li Shaobei, Liang Guohong, Zan Zhitao, Shi Lihong, Yan Wenbo, Liang Chao, Li Feifei, Chen Lipin, Fan Bolin, Wang Xuliang, Jiang Xuju, Chen Hongjian
School of Materials Science and Engineering, Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology, Tianjin, 300130, China.
School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
Sci Rep. 2017 Dec 1;7(1):16818. doi: 10.1038/s41598-017-16454-7.
Photo-assisted proton-exchange (PAPE) is carried out on the +c- and y-surfaces of Fe-doped LiNbO crystals and the impact of the crystal orientation on the PAPE and the subsequent photo-assisted chemical etching (PACE) is investigated. The proton distributions and the morphologies of the proton-exchanged surfaces are studied by using Micro-FT-IR, Micro-Raman, optical and scanning electron microscopy. Through the PAPE process the proton-exchange can be confined in a specific region by an incident laser beam with fixed intensity profile. It is found that the y-surface is much more fragile than the +c-surface and that micro-cracks are easily generated on the y-surface during the PAPE process. Moreover, the range and number of these micro-cracks can be controlled by the experimental parameters of the PAPE process. The etching morphology of the y-surface shows apparent directional features along the c-axis of LiNbO crystal and the proton spatial distribution is found elongated along the c-axis. Both effects are attributed to the accumulation of photovoltaic charges at the two sides of the illumination area along the c-axis.
在掺铁铌酸锂晶体的+c面和y面上进行光辅助质子交换（PAPE），并研究晶体取向对PAPE以及后续光辅助化学蚀刻（PACE）的影响。利用显微傅里叶变换红外光谱（Micro-FT-IR）、显微拉曼光谱、光学显微镜和扫描电子显微镜研究质子分布和质子交换表面的形貌。通过PAPE过程，质子交换可以通过具有固定强度分布的入射激光束限制在特定区域。研究发现，y面比+c面脆弱得多，并且在PAPE过程中y面上容易产生微裂纹。此外，这些微裂纹的范围和数量可以通过PAPE过程的实验参数来控制。y面的蚀刻形貌沿铌酸锂晶体的c轴呈现明显的方向性特征，并且发现质子空间分布沿c轴拉长。这两种效应都归因于沿c轴在光照区域两侧光伏电荷的积累。
