Self-assembly of Functional Groups Inside High Aspect Ratio Silicon Nanopores

摘要

In this study, development of a technique for self-assembly of molecules with functional end groups inside high aspect ratio silicon nanopores is reported, A 20-um thick porous silicon membrane with pore sizes of 5-7 nm was fabricated, The structure was then hydroxylated to enable silane-based self-assembly. A setup was fabricated to hold the membrane die between two chambers charged with dry helium. A 1 mM solution of 3-mercaptopropyl-trimethoxysilane (MPTMS) in benzene was supplied to the top side of the membrane. A constant flow of helium over the bottom of the membrane allowed continuous evaporation of the solvent from the bottom of the pores, so that the fresh solution could get into the pores from top The pores were charged with solvent approximately 10000 times, to supply enough MPTMS molecules to fill the estimated OH sites within the pores Penetration of the MPTMS molecules down to the bottom of the pores was verified by measuring sulfur variation through the membrane thickness using Time of Flight-Secondary Ion Mass Spectroscopy (ToF-SIMS) technique.