| 摘要 |
FIELD: chemistry.SUBSTANCE: method of increasing sensitivity of detecting toxic chemical vapour using a detector based on semiconductor sensors. Analysed air is ionised by ionising radiation sources of different types or a corona discharge generator, mounted in the detector housing in the immediate vicinity of the surface of a gas-sensitive layer of the semiconductor sensors. Upon falling into the active zone of radiation or in the region of corona discharge, molecules of toxic chemicals are ionised, thereby losing electrons and acquiring a positive charge. As a result of chemisorption, molecules of the analyte substance transform into charged adsorption form onto the surface of the gas-sensitive layer of the semiconductor sensors. Due to the charged form of chemisorption, the probability of interaction of the molecules with active centres of the surface of the gas-sensitive layer increases and, consequently, the rate of adsorption increases, which increases sensitivity of detecting toxic chemical vapour in air 5?10 times. Also, when heating temperature of the gas-sensitive layer increases (reduction of the potential barrier and change in temperature gradient), the probability of desorption of charged molecules also increases, which reduces the relaxation time of the surface of the sensor.EFFECT: high sensitivity of detecting toxic chemical vapour in air using a detector based on semiconductor sensors. |
