Dedicated semiconductor sensors have high sensitivity and provide rapid detection, they are used in order to monitor and provide early warning of potential threats. However, these types of devices have a drawback – low specifity. In order to improve it, it is necessary to find a new approach to the working principles of a sensor. The goal of the article is to evaluate the possibility of improving specificity for transistor based sensors using optical radiation. The article presents precise results, confirming the possibility of creating new sensor on the transistor and optical radiation base.