title: Signal-to-Noise Enhancement of a Nanospring Redox-Based Sensor by Lock-in Amplification.
abstract: A significant improvement of the response characteristics of a redox chemical gas sensor (chemiresistor) constructed with a single ZnO coated silica nanospring has been achieved with the technique of lock-in signal amplification. The comparison of DC and analog lock-in amplifier (LIA) AC measurements of the electrical sensor response to toluene vapor, at the ppm level, has been conducted. When operated in the DC detection mode, the sensor exhibits a relatively high sensitivity to the analyte vapor, as well as a low detection limit at the 10 ppm level. However, at 10 ppm the signal-to-noise ratio is 5 dB, which is less than desirable. When operated in the analog LIA mode, the signal-to-noise ratio at 10 ppm increases by 30 dB and extends the detection limit to the ppb range.
authors.affiliation: Department of Physics, University of Idaho, Moscow, ID 83844, USA. bakharevpavel@gmail.com.
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Bakharev
authors.affiliation: Department of Physics, University of Idaho, Moscow, ID 83844, USA. dmcilroy@uidaho.edu.
authors.forename: David N
authors.initials: DN
authors.lastname: McIlroy
keywords: MOS; ZnO; gas sensor; lock-in amplifier