A silicon photodiode structure was studied for the spectral analysis of optical radiation. The structure consists of oppositely-directed barriers. We developed a model of the electronic processes occurring in the structure. The possibilities of the selection of separate waves from the integral flux of radiation, the wave absorption and the quantitative spectral analysis of the waves of the model for contaminated environment were investigated. An algorithm was developed for carrying out the spectral analysis without the preliminary calibration, and for promoting a possible creation of a new type of a portable semiconductor spectrophotometer.