Quantitative analysis of the sensitivity of porous silicon optical biosensors

The optical response of porous silicon affinity biosensors depends strongly on their nanomorphology because the sensing species does not completely fill the pores but is instead attached to the pore walls. The performance and sensitivity of porous silicon microcavity biosensors are calculated as a function of pore size using a simplified effective medium approximation. Excellent agreement is obtained between the model predictions and the experimental results after binding of aminopropyltriethoxysilane and glutaraldehyde in mesoporous and macroporous silicon microcavities. Detection of layers thinner than 0.01 nm should be possible. (c) 2006 American Institute of Physics.