“…Since the macropore fabricated on n-type silicon was first reported in 1970's [1], it has attracted great attention for many applications, such as photonic crystals [2][3][4][5][6], field effect transistors (FETs) [7,8], high-density silicon capacitors [9][10][11][12][13][14], templates [15], through silicon vias [16,17], microneedles [18][19][20][21], microfluidics [22,23], heat sinks [24], neutron detectors [25,26], and so on. Among all of them, the crucial problem is to fabricate controllable and homogeneous macropore arrays, especially for high-aspect-ratio ordered macropores.…”