Brief introduction of semiconductor gas sensors

Some gas sensitive devices (also known as gas sensor) is a kind of gas, some oxidizing atmosphere reducing gas and electronic devices, organic solvent vapor is very sensitive, is widely used in the detection of combustible gas and toxic gas leak detection, alarm monitoring and other fields.
A complete gas sensing device is composed of explosion-proof, tube, electrode, glass substrate, heater and oxide semiconductor and other parts, its structure is shown in figure 1.
The core part of gas sensors is metal oxide semiconductor, such as two tin oxide. The metal oxide semiconductor can adsorb oxygen in the air at a certain temperature to form negative ion adsorption of oxygen, thereby reducing the electron density in the semiconductor material and increasing the resistance. When flammable gas or poison gas is encountered, the adsorbed oxygen will be desorbed, and the combustible gas or poison gas will be adsorbed on the surface of the semiconductor material in a positive ion state. Because the electrons are released in the process of desorption and adsorption, the electron density is increased, so that the resistance is reduced. In the device, the heater is used to increase the sensitivity of the device.
When purchasing gas sensors, you must request device specifications from the merchant.
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