In this work, a thin-film transistor gas sensor based on the p-N heterojunction is fabricated by stacking chemical vapor deposition-grown tungsten disulfide (WS2) with a sputtered indium–gallium–zinc-oxide (IGZO) film. To the best of our knowledge, the present device has the best NO2 gas sensor response compared to all the gas sensors based on transition-metal dichalcogenide materials. The gas-sensing response is investigated under different NO2 concentrations, adopting heterojunction device mode and transistor mode. High sensing response is obtained of p-N diode in the range of 1–300 ppm with values of 230% for 5 ppm and 18 170% for 300 ppm. On the transistor mode, the gas-sensing response can be modulated by the gate bias, and the transistor shows an ultrahigh response after exposure to NO2, with sensitivity values of 6820% for 5 ppm and 499 400% for 300 ppm. Interestingly, the transistor has a typical ambipolar behavior under dry air, while the transistor becomes p-type as the amount of NO2 increases. The assembly of these results demonstrates that the WS2/IGZO device is a promising platform for the NO2-gas detection, and its gas-modulated transistor properties show a potential application in tunable engineering for two-dimensional material heterojunction-based transistor device.

2D- and nanostructured metal sulfide materials promise to advance several gas sensing applications due to the abundant choice of materials with easily tunable electronic, optical, physical, and chemical properties. Of...

Owing to their sensitive chemical-to-electrical transducer capabilities and compatibility with deviee miniaturization and low operation temperature, single-walled carbon nanotube field-effect transistor (SWCNT-FET) represents an attractive platform to provide solutions in the gas sensing field. In this work, SWCNT-FETs were fabricated and their performances for detecting low NO2 concentrations were evaluated. Outstanding deviees response was obtained, which was shown to follow a 2 power law dependence between the response and the NOz concentration in the range of 100 ppb up to 10 ppm. Such ultra-high response is attributed to an enhancement of the Schottky barrier modulation triggered by the specifie deviee configuration. The deviee configuration is based on individual semiconducting SWCNTs directly connecting the interdigitated Source-Drain electrodes. To the best of our knowledge, the results reported here correspond to the most sensitive deviee among the deviees based on non-functionalized carbon materials and operational at low temperatures. Furthermore, the obtained results are supported by a deep SWCNT characterization, and the changes in Schottky barrier's height induced by the,presence of gas molecules are estimated and discussed. Overall, the present reported results provide useful information for establishing a robust process for the fabrication of the next generation of CNT based gas-sensing devices.