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Tuning the shape of macroporous silicon
Author(s) -
Trifonov T.,
Garín M.,
Rodríguez A.,
Marsal L. F.,
Alcubilla R.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200790017
Subject(s) - etching (microfabrication) , silicon , porous silicon , fabrication , materials science , membrane , nanotechnology , cover (algebra) , oxide , stripping (fiber) , photonics , optoelectronics , optics , layer (electronics) , chemistry , mechanical engineering , composite material , engineering , physics , medicine , biochemistry , alternative medicine , pathology , metallurgy
The cover picture shows SEM images of the porous silicon membranes with controlled pore geometry which are subject to this issue's Editor's Choice article [1]. The authors demonstrate how the rounded‐square shape of pores in a silicon membrane prepared by photo‐electrochemical etching can be turned into a circular cross section using multiple oxidation/oxide‐stripping cycles. The image on the left is a side view onto a cleaved sample after eleven oxidation steps. The enlarged inset shows pore walls as thin as about 250 nm, including one set of the slightly thicker marks produced by reducing the current in order to obtain feedback on the etching rate. One oxidation step further, the membrane releases individual silicon pillars with a very large aspect ratio, as is illustrated by the top view on the right. The first author holds a post‐doctoral position at the Electronics Department of the Technical University of Catalonia, where his research focuses on the fabrication of 2D and 3D photonic crystals based on macroporous silicon. Also featured on the cover is a Review Article by Chivukula et al., surveying the various types of acoustic‐wave devices utilizing surface‐acoustic, acousto‐optic and photo‐acoustic effects for applications in biology and medicine [2]. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)