Morphological and optical characteristics of porous silicon produced by anodization process in HF-acetonitrile and HF-ethanol solutions

Journal of the Brazilian Chemical Society

Cláudia R. B. Miranda¹  Maurício R. Baldan¹  Antonio F. Beloto¹  Neidenêi G. Ferreira¹ 

[1] ,Instituto de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais São José dos Campos SP ,Brazil

关键词: porous silicon;    HF-acetonitrile;    HF-ethanol;   

DOI  :  10.1590/S0103-50532008000400022

来源: SciELO

【 摘 要 】

Porous silicon (PS) samples were obtained by anodization etching process of n-type silicon wafer phosphorus-doped. Electrochemical oxidation of PS was investigated in aqueous hydrofluoric acid (HF) containing additive such as ethanol or acetonitrile. Pore formation was studied with the variation of type and resistivity of the silicon wafer, taking into account the most important anodization process parameters such as: acid concentration, current density and anodization time. Scanning Electron Microscopy (SEM) and Raman Scattering Spectroscopy measurements were used to characterize the macropore morphology changes and sample photoluminescense responses, respectively. PS layer formed in HF-acetonitrile solution showed more uniform and homogeneous macropore distributions with different shapes and sizes. Behavior may be explained because acetonitrile surface tension is greater than that of ethanol. Therefore, acetonitrile molecules might passivate the silicon surface dissolved during the anodization process.

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