Electrochemical impedance spectroscopy of oxidized porous silicon
Electrochemical impedance spectroscopy of oxidized porous silicon
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DOI：
10.1016/j.tsf.2014.01.044
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发表时间：
2014-04-01
期刊：
影响因子：
2.1
通讯作者：
Mascia, Michele
中科院分区：
文献类型：
--
作者：
Mula, Guido;Tiddia, Maria V.;Mascia, Michele
本文研究了多孔硅的电化学氧化过程。我们通过比较恒流电化学阻抗谱（EIS）测量结果和样品的光学镜面反射率，分析了层厚（1.25-22 μ m）和施加电流密度（1.1-11.1mA/cm(2)，参考外部样品表面计算的值）对氧化过程的影响。利用等效电路对EIS的结果进行解释，以分离不同样品部分的贡献。在薄样品和厚样品中发现了电化学氧化过程的不同行为：而对于薄样品，氧化过程与电流密度和厚度唯一相关，对于厚样品，这就不成立了。利用扫描电子显微镜进行的能量色散光谱测量证实，电化学氧化过程的不均匀性随着厚度和电流的增加而增加。提出了一种可能的解释来证明薄样品和厚样品在电化学过程中的不同行为。(C) 2014 Elsevier B.V.版权所有
We present a study of the electrochemical oxidation process of porous silicon. We analyze the effect of the layer thickness (1.25-22 mu m) and of the applied current density (1.1-11.1mA/cm(2), values calculated with reference to the external samples surface) on the oxidation process by comparing the galvanostatic electrochemical impedance spectroscopy (EIS) measurements and the optical specular reflectivity of the samples. The results of EIS were interpreted using an equivalent circuit to separate the contribution of different sample parts. A different behavior of the electrochemical oxidation process has been found for thin and thick samples: whereas for thin samples the oxidation process is univocally related to current density and thickness, for thicker samples this is no more true. Measurements by Energy Dispersive Spectroscopy using a Scanning Electron Microscopy confirmed that the inhomogeneity of the electrochemical oxidation process is increased by higher thicknesses and higher currents. A possible explanation is proposed to justify the different behavior of thin and thick samples during the electrochemical process. (C) 2014 Elsevier B.V. All rights reserved.