MEMS based Gas Sensing

Project by Turja Nandy

In this project, we will introduce MEMS membrane-based photo-acoustic (PA) detection system for a hazardous gas sensing application with high accuracy and low cost. We will use thin and deformable micro-machined SOI membrane to detect the acoustic vibration created via light-gas interaction inside the PA chamber. In this work, firstly, we will analyze the theory behind photo-acoustic phenomena and pressure change inside gas chambers for proper modeling of a MEMS membrane. Then, we will fabricate the MEMS membrane and prepare the whole optical experimental set-up with a LED-based infrared (IR) light source and detector according to the absorption spectra of target gases. Finally, we will detect the membrane deflection caused by acoustic vibrations and pressure change through a white light interferometer. These deflection values will give the sensitivity towards the particular gas.

Figure 1 3D printed photo-acoustic chamber model .

Figure 2 Bottom view of MEMS SOI membrane