High hydrosilylation efficiency of porous silicon SiHx species produced by Pt-assisted chemical etching for biochip fabrication

Porous silicon (PSi) prepared from Pt metal-assisted chemical etching (MaCE) was demonstrated to possess higher hydrosilylation efficiency (∼57%) than anodized PSi (∼11%) by surface reaction with ω-undecenyl alcohol (UO). Deconvolution of the SiH x ( x = 1-3) stretching bands revealed the abundance of SiH2 species on MaCE PSi was 53%, ∼10% higher than on anodized samples, while both of SiH1 and SiH 3 were ∼5% lower correspondently on MaCE PSi than on anodized samples. The surface SiH x abundances were suggested to account for the higher hydrosilylation efficiency on MaCE PSi. Optimization of Pt-assisted chemical etching parameters suggested a 7–15 nm thick Pt-coating and an etching time of 3–10 min for biochip applications. Scanning electron microscopy images revealed that an isotropic top meso-porous layer was beneficial for hydrosilylation and long-term durability under ambient conditions. To end, an example of histidine-tagged protein immobilization and microarray was illustrated. Combining the materials’ property, surface chemistry, and micro-fabrication technology together, we envision that silicon based biochip applications have a prosperous future.