We propose a tested, sensitive, and prompt COVID-19 breath screening method that takes
less than 1 min. The method is nonbiological and is based on the detection of a shift in
the resonance frequency of a nanoengineered inductor–capacitor (LC) resonant
metamaterial chip, caused by viruses and mainly related exhaled particles, when
performing terahertz spectroscopy. The chip consists of thousands of microantennas
arranged in an array and enclosed in a plastic breathalyzer-like disposable capsule kit.
After an appreciable agreement between numerical simulations (COMSOL and CST) and
experimental results was reached using our metamaterial design, low-scale clinical
trials were conducted with asymptomatic and symptomatic coronavirus patients and healthy
individuals. It is shown that coronavirus-positive individuals are effectively screened
upon observation of a shift in the transmission resonance frequency of about
1.5–9 GHz, which is diagnostically different from the resonance shift of healthy
individuals who display a 0–1.5 GHz shift. The initial results of screening
coronavirus patients yielded 88% agreement with the real-time quantitative polymerase
chain reaction (RT-qPCR) results (performed concurrently with the breath test) with an
outcome of a positive predicted value of 87% and a negative predicted value of 88%.
This work evaluates the defects in high quality atomic layer deposited (ALD) HfAlOx with extremely low Al (<3% Al/(Al + Hf)) incorporation in the Hf based high-k dielectrics. The defect activation energy estimated by the high temperature current voltage measurement shows that the charged oxygen vacancies, V+/V2+, are the primary source of defects in these dielectrics. When Al is added in HfO2, the V+ type defects with a defect activation energy of Ea ∼ 0.2 eV modify to V2+ type to Ea ∼ 0.1 eV with reference to the Si conduction band. When devices were stressed in the gate injection mode for 1000 s, more V+ type defects are generated and Ea reverts back to ∼0.2 eV. Since Al has a less number of valence electrons than do Hf, the change in the co-ordination number due to Al incorporation seems to contribute to the defect level modifications. Additionally, the stress induced leakage current behavior observed at 20 °C and at 125 °C demonstrates that the addition of Al in HfO2 contributed to suppressed trap generation process. This further supports the defect engineering model as reduced flat-band voltage shifts were observed at 20 °C and at 125 °C.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.