Electrochemical Preparation of In-Silicon Hierarchical Networks of Regular Out-Of-Plane Macropores Interconnected by Secondary In-Plane Pores Through Controlled Inhibition of Breakdown Effects

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• 作者：Chiara Cozzi ; Giovanni Polito ; Lucanos Marsilio Strambini ; Giuseppe Barillaro ; ^{g.barillaro@iet.unipi.it" class="auth_mail" title="E-mail the corresponding author}
• 关键词：hierarchical networks ; electrochemical etching ; breakdown inhibition ; photogeneration ; porous silicon ; hydrogen peroxide
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：1 January 2016
• 年：2016
• 卷：187
• 期：Complete
• 页码：552-559
• 全文大小：2443 K

文摘

In-silicon hierarchical networks of ordered out-of-plane macropores interconnected by high-density secondary in-plane pores are prepared by controlled electrochemical etching of n-type silicon in HF:H₂O₂ electrolyte through the synergistic use of back-side illumination, avalanche breakdown anodization voltage, and high-oxidizing-power chemical. Preparation of the hierarchical networks of pores is enabled by controlled inhibition of breakdown effects at high anodization voltages (in the breakdown region) through back-side illumination of the silicon electrode. Inhibition of breakdown effects in pre-patterned silicon electrodes etched under galvanostatic condition at high anodization voltages is used to simultaneously control formation of out-of-plane macropores by regulating the photogenerated etching current density flowing at the pore tips and enable in-plane branching of out-of-plane pores by increasing leakage current at the lateral pore surface through high voltage effects. Further, high-oxidizing-power chemical, namely H₂O₂, is used to increase density, length, and diameter of branching and, in turn, enable interconnection of out-of-plane macropores with in-plane secondary pores.