Thermal Modulation of SnO^sub 2^ Sensors for Alcohol Monitoring by Perspiration

In this paper a cyclical heating profile of Tin dioxide (SnO2) sensor is investigated. We propose to reduce power consumption while maintaining high sensitivity and good stability during monitoring of alcohol elimination by the skin trough the perspiration. This approach consists to operate the sensor micro-hotplate in pulse mode by switching on - off. The sensitive thin layer of SnO2 with a thickness of 50 nm was deposited by a magnetron reactive sputtering technique. Then, we studied the response of a SnO2 sensor under ethanol exposure to enable alcohol monitoring under a number of different power conditions (continuous and cyclical heating) in order to investigate the impact of reduced system level power consumption on sensor sensitivity. We demonstrated that this operating mode allows dividing by four the power consumption but results in a slight decrease of the sensitivity of the sensor of about 25 %.