Study of humidity sensors based on nanostructured carbon films produced by physical vapor deposition

In this study, carbon nanosheets and nanohoneycombs were synthesized on Si (1 0 0) substrates using a hot filament physical vapor deposition technique under methane ambient and vacuum, respectively. The four-point Au electrodes are then sputtered on the surface of the nanostructured carbon (n-C) films to form prototypical humidity sensors.The sensing properties of prototypical sensors at different temperature, humidity, direct current (DC), and alternative current (AC) voltage were characterized. Linear sensing response of sensors to relative humidity ranging from 11% to 95% is observed at room temperature. Experimental data indicate that the carbon nanosheets based sensors exhibit an excellent reversible behavior and long-term stability. It also has higher response than that of the humidity sensor with carbon nanohoneycombs materials.