Liu Junjun, Huang Zhifeng
Department of Physics, Hong Kong Baptist University (HKBU), Kowloon Tong, Hong Kong SAR, People's Republic of China.
Nanotechnology. 2015 May 8;26(18):185601. doi: 10.1088/0957-4484/26/18/185601. Epub 2015 Apr 15.
Engineering the porosity of silicon nanowires (SiNWs) is of fundamental importance, and this work introduces a new method for doing so. Metal-assisted chemical etching (MACE) of heavily doped Si(100) creates mesoporous silicon nanowires (mp-SiNWs). mp-SiNWs are transferred from the MACE-treated wafer to a sticky tape, leaving residues composed of broken mp-SiNWs and a mesoporous Si layer on the wafer. Then the taped wafer is re-treated by MACE, without changing the etching conditions. The second MACE treatment generates mp-SiNWs that are less porous and longer than those generated by the first MACE treatment, which can be attributed to the difference in the surface topography at the beginning of the etching process. Less porous mp-SiNWs reduce optical scattering from the porous Si skeletons, and vertically protrude on the wafer without aggregation to facilitate optical trapping. Consequently, less porous mp-SiNWs effectively reduce ultraviolet-visible reflection loss.
调控硅纳米线（SiNWs）的孔隙率至关重要，本文介绍了一种实现此目的的新方法。对重掺杂的Si(100)进行金属辅助化学蚀刻（MACE）可制备介孔硅纳米线（mp-SiNWs）。mp-SiNWs从经过MACE处理的晶圆转移至胶带，晶圆上留下由破碎的mp-SiNWs和介孔硅层组成的残留物。然后，在不改变蚀刻条件的情况下，对贴有胶带的晶圆再次进行MACE处理。第二次MACE处理产生的mp-SiNWs比第一次MACE处理产生的孔隙率更低且更长，这可归因于蚀刻过程开始时表面形貌的差异。孔隙率较低的mp-SiNWs减少了多孔硅骨架的光散射，并垂直突出于晶圆上而不发生聚集，便于光捕获。因此，孔隙率较低的mp-SiNWs有效降低了紫外-可见反射损耗。
