Thin films of In2O3/SiO for Humidity Sensing Applications

Abstract

This paper documents the manufacture and testing of a humidity sensor based on a combination of In 2 O 3 /SiO. A number of different sensor samples have been produced by thermal deposition and the effect of varying the vacuum pressure has also been investigated. The AC and DC conduction mechanisms have been investigated. From the AC conduction studies, the tunneling conduction mechanism has been observed at low frequencies and the hopping conduction mechanism, for the majority of sensor samples, has been observed at high frequencies. The DC conduction mechanisms have indicated the possibility of spacecharge-limited conduction. The sensor with the highest humidity sensitivity of 1.145%/RH% is 85%In 2 O 3 /15%SiO, which is produced at a vacuum pressure of 2×10 -4 mbar.From the point of view of temperature stability, the 55%In 2 O 3 /45%SiO samples produced at a vacuum pressure of 2×10 -4 mbar exhibit the lowest temperature sensitivity, 0.3%/ o C.

Facile synthesis and gas sensing properties of In2O3–WO3 heterojunction nanofibers

“…9, the responses of S3 to 25 ppm acetone in low and high RH air were 8.01, 7.8, 7.93, 7.64 and 7.84, respectively. Consequently, it is concluded that influence of RH to S3 is not significantly in 275 • C. WO 3 and In 2 O 3 have been widely investigated for applications in the field of humidity sensing, when the temperature is below 150 • C [42][43][44][45]. However, when the working temperature is higher than 150 • C, the humidity effect will not been taken into account.…”

Thin plasma-polymerized layers of hexamethyldisiloxane for humidity sensor development

“…Humidity sensors have been developed using different sensing materials such as ceramic, polymer and porous silicon [5][6][7]. This kind of sensors can be grouped into two types: resistive and capacitive types according to the output form of the sensor.…”

The study of electronic conduction in amorphous thin films of Al-In2O3-Al structure deposited by thermal evaporation

“…Thus the maximum field within the insulator film is kept to a minimum and there is little danger of more than one conduction processes being active. A number of investigations have been carried out on the frequency dependence of conductivity in many glassy and amorphous semiconductors [3][4][5][6][7][8]. It has been pointed out by Elliott [4] that a variety of conduction mechanisms can yield the ω s behaviour for the a.c. conductivity, but in general, it is difficult to establish which of the above effects determines the given observed conduction process.…”