Organic vapor detection using a color-difference image technique for distributed Bragg reflector structured porous silicon

To obtain an efficient response signal for organic vapors, a color-difference image technique is applied to a distributed Bragg reflector structured porous silicon (DBR PSi) sensor. The color-difference images were produced by the mathematical conversion of each pixel from surface interference color photographs of DBR PSi taken by a high-speed camera before and during exposure to an organic vapor. The sensitivity of this color-difference response signal was higher than the photoluminescence (PL) response, and the detectable concentration range was wider than the current response. Additionally, both the response and recovery times were faster than the other two responses.