The reason why semiconductor sensor uses low-dimensional nano tungsten oxide particles as sensitive materials is that the particles have high purity, large specific surface area, small particle size, uniform distribution, clean surface, low bulk density, easy dispersion, and excellent gas sensitivity, etc. More generally speaking, compared to traditional gas-sensitive materials, gas-sensitive materials made of nano-WO3 particles have faster response speed, better selection performance, and are more ecologically friendly, so they are suitable for detecting alcohol and gases such as nitrogen dioxide.
Semiconductor gas sensors are made by using the oxidation-reduction reaction of gas on the surface of semiconductors to change the resistance of sensitive components. They are a commonly used type of gas sensors and are widely used in industry, chemical industry, electronics, electric power, machine tools, petroleum and many other fields.
Its working principle is: when the semiconductor device is heated to a stable state, when the gas contacts the semiconductor surface and is adsorbed, the adsorbed molecules will diffuse freely on the surface of the object, losing the energy of movement, part of the molecules are evaporated, and the other part of the remaining molecules produce thermal decomposition and adsorption on the surface of the object. When the work ding of the semiconductor is less than the affinity of the adsorbed molecule, the adsorbed molecule will take away electrons from the device and become a negative ion adsorption. If the work ding of the semiconductor is greater than the dissociation energy of the adsorbed molecule, the adsorbed molecule will release electrons to the device to form a positive Ion adsorption. When the oxidizing gas is adsorbed on the n-type semiconductor and the reducing gas is adsorbed on the p-type semiconductor, the semiconductor carriers will be reduced and the resistance will increase.
Nano-tungsten oxide is an n-type semiconductor material, so it is often used to adsorb oxidizing gases, such as oxygen, nitrogen dioxide, and nitrogen monoxide.
