Fabrication of thin-film CuO/ZnO heterojunction and its humidity-sensing properties

The effect of relative humidity on the NO2 sensitivity of a SnO2/WO3 heterojunction gas sensor

“…However, it was also noted that the sensitivity of the sensor to NO 2 , S NO 2 , given by R NO 2 /R air , where R NO 2 is the sensor resistance at a given concentration of NO 2 and R air is the resistance in dry air, can vary between samples. Such differences are commonly seen in heterojunction sensor systems when the interface is formed by physically bringing together partly sintered bulk pellets, and are attributed to variations in the quality of the interface brought about by small differences in the overall contact pressure and contact area between samples [13,18]. In the current study, the sensor resistance increases by a factor of 2.4 per ppm increase in NO 2 concentration, this increase being attributed to the formation of an electrostatic barrier at the heterojunction interface through a build-up of surface charge following the adsorption of the target gas.…”

Heterocontact type CuO-modified SnO2 sensor for the detection of a ppm level H2S gas at room temperature

“…The p-n heterocontact concept is used in the present investigation, instead of adsorption-desorption mechanism, which was introduced in 1979 and has been applied as humidity sensors, liquid sensors and gas sensors [27][28][29][30][31][32][33][34]. The heterocontact concept was found to be very effective for the H 2 S gas sensing at room temperature.…”

CuO-doped BSST thick film resistors for ppb level H2S gas sensing at room temperature

“…The p-n heterocontact concept was used in the present investigation [18][19][20][21][22][23][24][25][26][27]. There is an intrinsic difference in the behavior between the heterocontact type sensors and the sensors based on catalytic oxidation/reduction of gas molecules.…”