A micro-system based on glass-nanoporous silicon for optical sensing of organic solvent vapor.
We present a recent experimental study on the application of nanoporous silicon (np-Si) to an optical vapor sensor. We fabricated the micro-system based on a glass-nanoporous silicon layer on a p(+)-type silicon wafer. To check the selectivity and sensitivity of the np-Si layer to organic vapors, we prepared three types of np-Si layer samples--a single layer, distributed Bragg reflector (DBR) layer, and microcavity layer--and investigated its reflectance spectra upon exposure to different concentrations of various organic vapors. When the np-Si layer samples were exposed to the organic vapors, a red-shift occurred in the reflectance spectrum, and we determined that this red-shift can be attributed to the changes in the refractive index induced by the capillary condensation of the organic vapor within the pores of the np-Si layer. The np-Si layer samples showed excellent sensing ability to different types and concentrations of organic vapors. After removing the organic vapors, the reflectance spectrum immediately returned to its original state.
Department of Physics, Kongju National University, Gongju-si, 314-701, South Korea.
Young-You
YY
Kim
Han-Jung
HJ
Kim
Ho-Jong
HJ
Kim
Dae-Geun
DG
Choi
Horchhong
H
Cheng
D003124:Colorimetry / Q000295:instrumentation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005740:Gases / Q000032:analysis*; D005898:Glass / Q000737:chemistry*; D008904:Miniaturization; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009930:Organic Chemicals / Q000032:analysis*; D010316:Particle Size; D016062:Porosity; D012031:Refractometry / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D012997:Solvents / Q000032:analysis*; D014159:Transducers
D005740:Gases; D009930:Organic Chemicals; D012997:Solvents; D012825:Silicon