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In addition to their visible motion such as swimming (e.g., with the help of flagella), bacteria can also exhibit nanomotion that is detectable only with highly sensitive instruments, and this study shows that it is possible to detect bacterial nanomotion using an AFM detection system. The results show that the nanomotion characteristics depend on the bacterial strain, and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium. ARTICLE HIGHLIGHTS: HIGHLIGHTS • Bacterial nanomotion can be detected by measuring AFM cantilever deflection. • Spectral analysis provides information about the self-oscillation features of different bacterial strains. • The nature of bacterial nanomotion is sensitive to bacterial food preferences. [ABSTRACT FROM AUTHOR]

Semiconductor quantum dots have attracted tremendous attention owing to their novel electrical and optical properties as a result of their size dependent quantum confinement effects. This provides the advantage of tunable wavelength detection, which is essential to realize spectrally selective photodetectors. We report on the fabrication and characterization of a high performance narrow band ultraviolet photodetector (UV-B) based on Indium oxide (In 2 O 3 ) nanocrystals embedded in aluminium oxide (Al 2 O 3 ) matrices. The In 2 O 3 nanocrystals are synthesized in an Al 2 O 3 matrix by sequential implantation of In + and [Formula: see text] ions and post-implantation annealing. The photodetector exhibits excellent optoelectronic performances with high spectral responsivity and external quantum efficiency. The spectral response shows a band-selective nature with a full width half maximum of ∼60 nm, and a responsivity reaching up to 70 A W -1 under 290 nm at 5 V bias. The corresponding rejection ratio to visible region was as high as 8400. The high performance of this photodetector makes it highly suitable for practical applications such as narrow-band spectrum-selective photodetectors. The device design based on ion-synthesized nanocrystals could provide a new approach for realizing a visible-blind photodetector.