@article{zhou_dieffenderfer_aleem_lee_misra_2024, title={A Novel Monolithic MEMS Array for E-Nose Applications}, volume={8}, ISSN={["2475-1472"]}, url={https://doi.org/10.1109/LSENS.2024.3355902}, DOI={10.1109/LSENS.2024.3355902}, abstractNote={In this letter, we present a novel monolithic microelectromechanical syste-ms (MEMS) matrix array that can be adapted for electronic nose (E-nose) applications. The proposed MEMS array consists of four heater rows and four sensing electrode columns, arranged in crossbars and resulting in 16 intersections, which sit on top of suspended membranes created by frontside isotropic dry etching. Power supply, fine-tuning, and wireless communication are integrated on a custom printed circuit board. Thin films of metal oxide are deposited on this matrix array via atomic layer deposition. The achieved E-nose is low power, ultrasensitive, fast, scalable, reliable, and repeatable. It responds to different volatile organic compounds (VOCs) through the identification of optimal operating temperature. For nitrogen dioxide, ethanol, and carbon monoxide (CO), optimal temperatures and measured lower detection limits are ∼150 °C, 6.67 ppb, ∼250 °C, 50 ppb, and ∼350 °C, 1 ppm, respectively. Calculated theoretical detection limits are orders of magnitude lower. At optimal conditions, response/recovery time is <1 min. By tuning temperature profiles, this E-nose can inherently separate VOCs in mixtures. The proposed array is a versatile platform, compatible with back end of line complementary metal–oxide–semiconductor (CMOS) technology.}, number={2}, journal={IEEE SENSORS LETTERS}, author={Zhou, Yilu and Dieffenderfer, James and Aleem, Mahaboobbatcha and Lee, Bongmook and Misra, Veena}, year={2024}, month={Feb} }
 @article{zhou_dieffenderfer_sennik_aleem_speight_vasisht_oralkan_lee_misra_2023, title={Performance of A Monolithic E-Nose Array Integrating MEMS and ALD Processing}, ISSN={["1930-0395"]}, DOI={10.1109/SENSORS56945.2023.10325054}, abstractNote={We demonstrate a novel electronic nose (E-nose), which combines microelectromechanical systems (MEMS) and atomic layer deposition (ALD) technologies. MEMS micromachining creates a monolithic microheater array, consisting of independently controlled rows. By changing temperature profiles, a wide range of sensing surfaces are available. Sensor electrodes are arranged in crossbars with microheater rows. SnO2 thin film is deposited on this array as sensing materials by ALD. This E-nose demonstrates excellent fundamental operating characteristics such as speed and repeatability. It is ultra-sensitive against multiple volatile organic compounds (VOCs). It can also intrinsically separate VOC mixtures by tuning its operating modes.}, journal={2023 IEEE SENSORS}, author={Zhou, Yilu and Dieffenderfer, James and Sennik, Erdem and Aleem, Mahaboobbatcha and Speight, Jakob and Vasisht, Shrey and Oralkan, Omer and Lee, Bongmook and Misra, Veena}, year={2023} }