A feasible simulation method for vapor sensor based on polymer-coated NEMS diaphragm

To improve the performance of the vapor sensor based on polymer film-coated NEMS diaphragm embedded with piezoresistive silicon nanowires (SiNWs), a new method for calculating the inner strain distribution in a SiNWs and an investigation of the interactions between polymer film and NEMS diaphragm using finite element analysis is presented in this paper. In the model, the swelling stress of the polymer film due to absorption of the organic vapor is equivalent to a thermal expansion stress which leads to the deformation of the SiNWs. Meanwhile, an equivalent relation between temperature load and vapor concentration load is presented. Then, the simulation outputs of the NEMS vapor sensor are obtained. Compared with experimental results, the simulation results agree well with experimental results of the sensor. This method will be useful for optimizing the performance of this kind of vapor sensor.