Macroporous silicon templated from silicon nanocrystallite and functionalized Si-H reactive group for grafting organic monolayer.
This paper reports the development of a new fabrication process for highly porous and highly functional macroporous silicon (m-PSi). This new fabrication process involves two steps of electrochemical etching and one step of sonication detachment, and it uses silicon nanocrystallites as a template to form a honeycomb-like macroporous structure. The surface fabricated by this process has been characterized in comparison with the m-PSi surface fabricated by a one-step etching process. Scanning electron microscopy (SEM) images show that both m-PSi surfaces have nearly similar pore diameters (1-2 microm), but their porous microstructures are very different: the surface fabricated by two-step etching exhibits a smooth and shallow pore structure, while the other surface exhibits a rough and deep pore structure. Fourier transform infrared spectroscopy (FTIR) analyses reveal that the former is functionalized with a reactive Si-H group, while the latter is functionalized with a stable Si-O-Si group. To evaluate the Si-H reactive group, an allyl polyethylene glycol (PEG) is employed to modify the surface through hydrosilylation. SEM, FTIR, X-ray photoelectron spectroscopy, and water contact angle measurements are used to characterize the PEG-grafted m-PSi surface. PEG-grafted m-PSi substrates may have wide applications in biosensors, chemosensors, and biochips.
Guo
Dong-Jie
DJ
Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China. dongjie.guo@colorado.edu
Wang
Jing
J
Tan
Wei
W
Xiao
Shou-Jun
SJ
Dai
Zhen-Dong
ZD
D015374:Biosensing Techniques / Q000379:methods; D004563:Electrochemistry; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D013499:Surface Properties
D017655:Silicon Compounds; D011092:Polyethylene Glycols; D012825:Silicon