Abstract
Humidity, along with temperature, is one of the most important environmental variables in people’s lives. The control of humidity is an important matter that is related to material properties and stability in various industries, as well as basic living. In order to detect humidity, changes in the physical, chemical, and electrical properties of materials related to humidity are used, and studies using various methods are conducted. In this study, a field-effect transistor (FET) device was fabricated on a soft polymer substrate with SnO2 nanowires (NWs), whose electrical properties change in response to water molecules. The SnO2 NWs, synthesized by chemical vapor deposition (CVD), were transferred onto a polymer substrate, using a sliding transfer method. The NW FET device, which was connected to an aluminum (Al)-based radio frequency (RF) receiving antenna, was wirelessly operated as a humidity sensor, based on the change in electrical properties of SnO2 NWs according to the relative humidity (RH). It was configured with a wireless antenna and light emitting diode (LED) indicator to implement a soft wirelessly powered humidity sensor that senses high RH and is expected to be used as a wearable electronic/sensor in the future.
Highlights
IntroductionThe methods that measure the change of capacitance and resistance, which can be implemented in a thick- or thin-film form and utilize electrical characteristics, are the fields that have been studied most frequently
Humidity is generally measured as the relative humidity (RH), using hygrometers, including (i) the hair hygrometer that measures the changes in mechanical properties, mainly length, of the material by humidity [1]; (ii) the dry and wet bulb hygrometer that measures evaporation heat by evaporation [2,3]; (iii) the quartz oscillator dew point hygrometer that measures oscillation frequency change of piezoelectric quartz [4]; (iv) the capacitive humidity sensor that measures the change in capacitance of polymer or ceramic films [5,6,7,8,9]; and (v) the nano material-based humidity sensor that measures the resistance change of metal oxide nanomaterials [10,11,12,13,14,15]
It is mainly composed of thin or thick film layers and has been studied in a variety of ways, from single layers to heterogeneous multilayers [7,16,17,18,19]. The latter method, which measures the resistance change of nanomaterials and calculates humidity, uses a simple structure that shows the electrical resistance change of a material depending on the water molecules and uses a more complex field-effect transistor (FET) structure that can enhance the changes in the resistance range due to an electrical field
Summary
The methods that measure the change of capacitance and resistance, which can be implemented in a thick- or thin-film form and utilize electrical characteristics, are the fields that have been studied most frequently The former method measures the change in minute capacitance by water molecules adsorbed on the surface of the material. It is mainly composed of thin or thick film layers and has been studied in a variety of ways, from single layers to heterogeneous multilayers [7,16,17,18,19].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
