An investigation on the surface states evolution of polycrystalline silicon nanowires for gas sensing application

We perform a feasibility study on the application of thin film polycrystalline silicon (polysilicon) nanowires for gas sensing application upon exposure into different gas ambient. The nano-sensors are developed in a relatively cheap reactive ion etching system using a low-density plasma based etch and mature 3 micron lithography. Systematic measurements in air, vacuum, hydrogen and isopropyl alcohol demonstrate promising gas sensitivity and impressive response/recovery times in room temperature. The modification of surface states in nanowires upon exposure into different gas ambient is confirmed through 3D numerical simulation. This investigation demonstrates the potential of polysilicon nanowires for detecting molecules in gas phase thereby reveals that the polysilicon nanowire sensor is promising for a simple, low cost, manufacturable route for gas-sensor fabrication.