Nano Lett. 18, 190–201 (2018)

The broadband nature of silicon detectors means that while they are capable of detecting visible light they are unable to distinguish between distinct colours without the use of colour filters, adding complexity. Now, a team of Israeli scientists from Tel Aviv University and Technion have fabricated silicon nanowire detectors (20 × 300 nm in size) that are only sensitive to specific colours. The spectral selectivity originates from covalently attaching different organic fluorophores that absorb light of a specific wavelength and inject electrons into the nanowire. These photoinduced electrons change the conductivity of the nanowire, a change that can be electrically sensed in a field-effect transistor configuration. A variety of nanowire detectors functionalized with Alexa-610, Alexa-555, Alexa-488 and Alexa-430 fluorophores, so that they responded to red, green, blue and violet light, respectively, were fabricated.

Credit: American Chemical Society