应用于光电阴极的SiO_(2)纳米孔阵列

SiO_(2) Nanohole Arrays for Photoelectrocathode Applications

目前以正电子亲合势K2CsSb为代表的光电发射阴极材料因其有源层较薄的特征使其光吸收能力较差,现成为限制其提升性能的重要因素之一。以聚苯乙烯(PS)纳米球剥离法制备的金属孔阵为掩膜,在SiO2衬底上刻蚀制备纳米孔阵列。首先刻蚀单层自组装PS纳米球以改变尺寸,然后在表面沉积镍膜并进行剥离获得孔阵掩膜,最后刻蚀SiO_(2)衬底并去除掩膜获得孔阵。通过改变PS纳米球的自组装和刻蚀工艺参数实现了对纳米孔阵的孔径、深度、周期等几何参数的灵活调节,并通过优化离子刻蚀的频率、反应气体配比等参数有效降低了纳米孔刻蚀面的粗糙度,最后结合实验测试和理论仿真探索了其光学特性,研究结果表明纳米孔阵列能够提高光电发射器件的光吸收率,具有重要应用价值。

Currently,the photoelectron emission efficiency of the K,CsSb positive electron affinity photocathodes is mainly limited by the low light absorption in the ultra-thin active layers.In this work,the SiO2 nano-hole arrays that fabricated by ICP etching were used to improve the light absorption in K,CsSb.A polystyrene(PS)nano-sphere monolayer was prepared on SiO2 substrate by self-assembling and the sphere size was adjusted by etching.Then,a nano-hole array mask was prepared by depositing the nickel film and striping the PS sphere,Finally,a nano-hole array was fabricated by etching the SiO2 substrate and removing mask.The surface morphologies,geometries and optical properties of the fabricated nano-hole arrays were characterized and analyzed.The ordered SiOz nano-hole arrays with controllable size and good morphology were obtained under the optimized process conditions,which show the excellent light management performances and match the requirements of actual photocathode applications.