Reduction of Interference Between pH and Optical Output Signals in a Multimodal Bio-Image Sensor

A low-interference multimodal sensor for pH and optical imaging has been developed. The interference signal that occurs between pH and the optical outputs is found to be caused by photogenerated electrons during pH sensing. This interference could be suppressed by adding another charge-accumulation region to a conventional multimodal sensor structure in order to measure only photogenerated electrons. Conventional pH sensing devices combine accumulation regions for photo generated electrons, thereby discriminating between pH and optical signals.