A study on reactivity of p(+) porous silicon layers (PSL) to different gas atmosphere has been carried out. Substrate doping was 5-15 m Omega cm and 0.5 Omega cm, porosity ranged from 30 to 75% and the thickness of the porous layers was 20-30 mu m. Three different processes to insure good electrical contact are proposed and discussed. PSL were kept at constant bias and current variations due to interaction with different concentrations of NO(2) were monitored at constant relative humidity (R.H.). Measurements were performed at room temperature (R.T.) and at atmospheric pressure. Concentrations as low as 1 ppm were tested, but the high sensitivity of the sensor makes possible to test lower values. The recovery time of the sensor is of the order of one minute. Response to interfering gases (methanol, humidity, CO, CH(4), NO, NO(2)) has been examined also. In-situ FTIR spectroscopy in NO(2) atmosphere shows a fully reversible free-carrier detrapping in the IR region. confirming the validity of the models proposed in the recent past for electrical conduction in mesoporous silicon. (C) 2000 Elsevier Science S.A. All rights reserved.
NO2 monitoring at room temperature by a porous silicon gas sensor / Boarino, Luca; Baratto, C; Geobaldo, F; Amato, Giampiero; Comini, E; Rossi, ANDREA MARIO; Faglia, G; Lerondel, G; Sberveglieri, G.. - In: MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY. - ISSN 0921-5107. - 69:(2000), pp. 210-214. [10.1016/S0921-5107(99)00267-6]
NO2 monitoring at room temperature by a porous silicon gas sensor
BOARINO, LUCA;AMATO, GIAMPIERO;ROSSI, ANDREA MARIO;
2000
Abstract
A study on reactivity of p(+) porous silicon layers (PSL) to different gas atmosphere has been carried out. Substrate doping was 5-15 m Omega cm and 0.5 Omega cm, porosity ranged from 30 to 75% and the thickness of the porous layers was 20-30 mu m. Three different processes to insure good electrical contact are proposed and discussed. PSL were kept at constant bias and current variations due to interaction with different concentrations of NO(2) were monitored at constant relative humidity (R.H.). Measurements were performed at room temperature (R.T.) and at atmospheric pressure. Concentrations as low as 1 ppm were tested, but the high sensitivity of the sensor makes possible to test lower values. The recovery time of the sensor is of the order of one minute. Response to interfering gases (methanol, humidity, CO, CH(4), NO, NO(2)) has been examined also. In-situ FTIR spectroscopy in NO(2) atmosphere shows a fully reversible free-carrier detrapping in the IR region. confirming the validity of the models proposed in the recent past for electrical conduction in mesoporous silicon. (C) 2000 Elsevier Science S.A. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
