Photoelectrochemical etching of Si and porous Si in aqueous HF

Autor:	Lynne Koker, Kurt W. Kolasinski
Rok vydání:	2000
Předmět:	Reaction rate Crystal Photoluminescence Chemical engineering Quantum dot Chemistry General Physics and Astronomy Mineralogy Physical and Theoretical Chemistry Thin film Porous silicon Dissolution Isotropic etching
Zdroj:	Physical Chemistry Chemical Physics. 2:277-281
ISSN:	1463-9084 1463-9076
DOI:	10.1039/a908383i
Popis:	The irradiation of n-type Si(111) submerged in HF(aq) with a UV, visible or IR laser can lead to the formation of photoluminescent porous silicon (por-Si) thin films. We demonstrate that two distinct photoelectrochemical etching processes are induced by illumination: anisotropic etching, which leads to pore formation and propagation, and isotropic etching, which removes por-Si. As a result, both the solution/por-Si and the por-Si/c-Si interfaces assume shapes that are determined by the laser intensity profile. A counter reaction occurs in a spatially separate region of the crystal. A dark reaction between the por-Si and HF(aq) has also been observed. The photoelectrochemical reaction rates, after an initial increase, approach a constant value. The porous film increases steadily in thickness, while it continues to descend deeper into the crystalline Si. We discuss a mechanism for the formation and dissolution of the por-Si which emphasizes the effects of quantum confinement within the por-Si.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5aa5d224de2366f6235beae44c3fba8b https://doi.org/10.1039/a908383i Zobrazit plný text záznamu