Crystallographic Research, Macropore Membranes and Material Customization
Recent studies explore the properties and production methods of porous silicon-based materials.
A Blog Post by Pablo Markin.
On October 5, 2018, Shannon C. Knight, Bret A. Unger and Kurt W. Kolasinski have published an article entitled “Crystallographically Defined Silicon Macropore Membranes” in Open Material Sciences. In their article, Knight, Unger and Kolasinski indicate that “[c]ellular development responds in a complex manner to an array of chemical and geometrical cues” (33). This study explores “the formation of macropore membranes in which the macropores extend” (34). Previous research results have demonstrated that one can use “diffraction to modulate the laser intensity profile, which in turn modulates the formation of pillars in a regular fashion” (36). This research has also indicated that “[a] reproducible non-serial method of making patterned membranes in silicon containing crystallographically defined rectangular and octagonal through pores with widths in the range of 4–12 µm and membrane thicknesses in excess of 100 µm” (39) is technically feasible.
Similarly, in their paper, titled “Optical interferometry and photoacoustics as in-situ techniques to characterize the porous silicon formation: a review” and published on July 25, 2018, in Open Material Sciences, Cristian F. Ramirez-Gutierrez, Jorge D. Castaño-Yepes and Mario E. Rodriguez-Garcia have argued that “[p]orous silicon (PSi) is a groundbreaking material because its physicochemical properties can be customized through its porosity” (23). These authors also add that “the physical modification of the well-known materials, like silicon and carbon, […] is a constant requirement, particularly for the optoelectronic industry” (23). As Ramirez-Gutierrez, Castaño-Yepes and Rodriguez-Garcia clarify, “[t]hese modifications are related to structure, morphology, and dimensionality. […] Porous silicon (PSi) is an excellent example of the new functionality of crystalline silicon (c-Si)” (23).
Consequently, as this study demonstrates, PSi is “a versatile material for optoelectronics, chemical sensing, an anode for lithium batteries, among others applications in several fields” (30). As this research further suggests, “the growth of PSi or the process to make porous requires the implementation of real time (in-situ) techniques that can provide control and accuracy in the physicochemical properties” (30). The scholarly contribution of this study is the elaboration of “a methodology for the real-time monitoring of multiple parameters of PSi, such as the velocity formation, porosity profile, refractive index, and roughness […] [that] allows studying the effect of the electrolyte composition and temperature to characterize the evolution of surface morphology” (30).
By Pablo Markin
Featured Image Credits: sample prep1, Berkeley, California, United States, August 24, 2010 | © Courtesy of Daniel Parks/Flickr.