Ion balance detection using nano field-effect transistor with an extended gate electrode

We developed a nano field-effect transistor (nanoFET) sensor for detecting ions in the air. Air ions can be measured using a commercial ion counter; however, it is large and expensive equipment, requires airflow to be through a cylinder type electrode or the plate electrode. NanoFET sensor is suitable for monitoring the ion generator module in home appliances like air purification. A nanoFET sensor can continuously measure the ion balance to monitor the performance of the ion generators which do static electricity elimination in electronics manufacturing lines. In this study, we developed a semiconductor sensor that can measure the ion balance in the air. The sensor is a nanoFET device with an extended gate electrode. The polarity of the ions adsorbed on the extended gate electrode is measured, and consequently, the ion imbalance is quantitatively estimated. The developed device enables reset with a switch connected to the extended gate. The sensor reads out with a current to voltage converting operational amplifier, a reset switch, and a microprocessor. We expect that the developed nanoFET sensor is practically applied to monitor the malfunction of ion generators in the air cleaner and in the static electricity elimination in electronics manufacturing lines.