A multi-bit fully integrated thin-film transistor NO2 gas detector at room temperature

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Mani Teja, et al., “A multi-bit fully integrated thin-film transistor NO2 gas detector at room temperature”, IEEE sensor letters 4 (8), 2020, 5501204.

Inexpensive and compact gas sensing systems are indispensable for accurate air quality monitoring with broad spatial coverage. We report an InGaZnO thin-film transistor (TFT)-based integrated NO 2 gas detection system that yields a digital output proportional to the NO 2 concentration. This is the first report on integrated TFT-based detectors where gas concentration is quantified and where simultaneous digital output is provided without additional signal conditioning or analog to digital conversion circuits. It is a low power consuming system with consumption in the order of a few microwatts. It constitutes a highly sensitive and selective fabricated InGaZnO TFT gas sensor operable at room temperature. The response of the TFT in the presence of the NO 2 as a sensor is evaluated, and it is reproducible with the measured limit of detection as 100 ppb. Such standalone thin-film electronic systems that function as gas-sensitive analog to digital converters pave the way to compact and inexpensive gas sensing systems.