In2S3 vacuum pressure sensor through a simple two-step process

We demonstrate here an In2S3 based vacuum pressure sensor that can operate over a vacuum range, 103–10−3 mbar at room temperature. It is shown that vacuum pressure has a significant electrical impact on the sensitivity and the sensor response of the device. The sensor response of the device in terms of the rate of resistance change is 183 with a quick rise/fall time of 3.3/1.7 s. Even after being exposed to ambient conditions for 8 weeks, the device displays a consistent and periodic sensor response for 100 consecutive vacuum on/off cycles, demonstrating its durability. X-ray photoelectron spectroscopy was used to identify the surface adsorbed/chemisorbed groups, which are responsible for vacuum sensing properties. These surface effects were further confirmed by exposing the device to different environments such as humidity, high temperature, and high purity oxygen. Though In2S3 is known for its properties as a buffer layer in solar cells, this study reveals another potential application of In2S3 thin films as a vacuum pressure sensor.