Capstone Project
| Group | 2008-10 | Status | completed |
| Title | Gas Sensor | ||
| Supervisor | Dr. M. Kahrizi | ||
| Description | Gas detectors play a major role in biomedical, chemical and environmental industries. For instance, an electronic nose (E-Nose) contains a number of gas sensing electrochemical cells. Breakdown ionization sensors, work by fingerprinting the ionization breakdown voltage of the unknown gas (Vb), and therefore, display a good selectivity. In these devices, electron impact ionization mechanism leads to the breakdown of gas. Since Vb is a unique quantity of each gas, by measuring this voltage, the existence and the type of the unknown gases can be found. Normally, Vb is in the range of several hundred to thousand volts for two parallel electrode plates which makes it difficult and hazardous to employ in many environments. Recently we have developed (micro-fabrication and micro-devices labs) a miniaturized gas sensor based on nanowires. The breakdown voltages for the device are several hundred voltages less than those obtained for parallel plate devices. The structure of the device needs to be modelled and optimized. In this context, we are developing a simulation tool to model the device. Our model which is based on combined Particle-In-Cell and Monte-Carlo-Collision (PIC-MCC) approaches provides a platform for further development and optimization of the device. Particle-in-cell (PIC) codes model the plasma using discrete particles, each representing many charged particles. The elastic and inelastic particle collisions are treated using the MCC method. For this we have used an open source simulator XOOPIC which includes Monte Carlo collision (MCC) algorithms for modelling collisions of charged particles with a variety of gases, including such effects as ion/neutral charge exchange, elastic electron scattering, and inelastic scattering due to electron. There is already a simulation tool in the market to model the parallel plates device for single atom gases like N, Ar, He. In this project students will develop a simulation tool based XOOPIC (an open source tool available and can be downloaded from internet) to model the device for various multi-atoms gases like O2, SF6, CH4, and CF4. |
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| Number of Students | 4-5 | ||
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| Comments: | Two separate groups can work on this project. | ||
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