Porous silicon vapor sensor with phase detection electronics

摘要: A novel vapor sensor is presented comprising a capacitive porous silicon (PS) transducer and phase-detection electronics. Sensing of ambient concentration by adsorption-diffusion-condensation kinetics molecules, the PS layer leading to change its dielectric constant modeled with an effective medium approximation (EMA). simple but precise phase sensitive electronic circuit has been developed. This detects any sinusoidal signal transmitted through correlates concentration. The tested in combination detection circuitry case relative humidity. Excellent linearity over entire range humidity achieved. Experimental results show resolution better than 0.1% accuracy 2% (near transition region) (otherwise). response time less 10 sec. good stability.