Comparison of amorphous silicon photodiodes and photoconductors for detection of quantum dot biomolecular tags

A comparative study of the performance of hydrogenated amorphous silicon photosensors based on two different device configurations for integration in a microarray platform for biomolecular detection is presented. A perpendicular contact p-i-n photodiode and a parallel contact intrinsic photoconductor, both with an integrated fluorescence filter, are microfabricated for the detection in solution of the fluorescence of the quantum dot Evitag 604 nm, a tag commonly used to label biological molecules. The minimum quantities of quantum dot detected by the p-i-n photodiode and the parallel contact photoconductor were 1 fmol (0.1 nM) and 30 fmol (3 nM), respectively.