Scanning electron microscopy image of a silicon nanowire array planarization. (a) After growth, the AAO template is filled with silicon nanowires which grew out of it. (b) Sonication of the sample breaks the outer nanowires revealing the post-growth AAO surface. (c) I-KI gold etching and ICP silicon etching leads to the planarization of the nanowire array. (d) Cross section showing the ‘top-down like’ nanowire array with a very good homogeneity of length and high density after alumina removal by HF etching. (e) Close view of the interface between the Si (100) substrate and the individualized nanowires. (f) Empty AAO template before gold catalyst electrodeposition, complementary to the geometry of (e).
Dupré et al. Nanoscale Research Letters 2013 8:123 doi:10.1186/1556-276X-8-123