ABSTRACT This paper presents a study of the effects of ablation direction, beam profile and outer environment on the width and morphology of micro-grooves ablated by a 10-ps, 532-nm laser with a changing range of fluences and scan speeds on 600 nm-thick CIGS (CuIn(1-x)Ga2Se x ) thin films. Experiments show that rear-side ablation by picosecond laser with a flat top beam in water environment yields a larger groove width than normal front-side ablation with a Gaussian beam in air, which is attributed to different material removal mechanisms, uniform energy distribution and the refraction of laser in water. The heat-affected zone and irregular edges induced by the tearing effect are the main defects of groove morphology associated with front- and rear-side ablation processes, respectively. Our studies indicate that flat top beam ablation, in general, inhibits the over-ablation in the central region, thereby improving the uniformity of grooves, though it does not eliminate the heat-affected zone and irregularity of two edges. The straightness of groove edges is further improved with the flat top beam ablation carried out in a water environment, resulting from the action of the shock wave in water. Hence, the nearly perfect micro-grooves can be fabricated with rear-side flat top beam ablation under water, which are characterized by steep sidewalls, straight edges and intact glass substrate without cracks.

中文翻译：

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CIGS（CuIn（1-x）Ga2Sex）薄膜上高质量微槽的皮秒激光烧蚀

摘要 本文研究了烧蚀方向、光束轮廓和外部环境对 10 ps、532 nm 激光烧蚀的微槽宽度和形态的影响，其能量密度和扫描速度范围在 600 nm 上变化。 -厚 CIGS (CuIn(1-x)Ga2Se x ) 薄膜。实验表明，在水环境中使用平顶光束的皮秒激光背面烧蚀比在空气中使用高斯光束的正常正面烧蚀产生更大的凹槽宽度，这归因于不同的材料去除机制、均匀的能量分布和激光在水中的折射。撕裂效应引起的热影响区和不规则边缘分别是与正面和背面烧蚀过程相关的凹槽形态的主要缺陷。我们的研究表明，平顶光束烧蚀，一般来说，抑制了中心区域的过度烧蚀，从而提高了凹槽的均匀性，但并没有消除热影响区和两个边缘的不规则性。由于在水中冲击波的作用，在水环境中进行平顶梁烧蚀，进一步提高了凹槽边缘的直线度。因此，近乎完美的微槽可以通过水下后侧平顶梁烧蚀来制造，其特点是侧壁陡峭、边缘直、玻璃基板完整无裂纹。由于在水中冲击波的作用，在水环境中进行平顶梁烧蚀，进一步提高了凹槽边缘的直线度。因此，近乎完美的微槽可以通过水下后侧平顶梁烧蚀来制造，其特点是侧壁陡峭、边缘直、玻璃基板完整无裂纹。由于在水中冲击波的作用，在水环境中进行平顶梁烧蚀，进一步提高了凹槽边缘的直线度。因此，近乎完美的微槽可以通过水下后侧平顶梁烧蚀来制造，其特点是侧壁陡峭、边缘直、玻璃基板完整无裂纹。