A gas-sensitive SPIM for detection ethanol using SnO2 as sensing element

摘要

Scanning photo-induced impedance microscopy (SPIM) is a method to detect a local impedancechange on the sensor surface [1]. In this study, tin dioxide (SnO2) film is deposited on sensor surface byvacuum evaporation [2] as a sensing material to detect ethanol [3]. The impedance change of the SnO2 filmin response to ethanol is read out in the form of an ac photocurrent signal, generated by a focused laserbeam modulated at 3.5 kHz. A schematic of the fabricated structure is shown in Fig. 1a.