Figure 5: Demonstration of detection capability.

Testing image detection capability under low-intensity light at wavelengths of 540, 1,310 and 1,550 nm. (a) Schematic representation of the point-by-point scanner set-up used to test the image capture capability of DTTM active antenna-based devices. (b) Images captured by a professional digital camera under light at wavelengths of 540 nm. (c–e) Bar chart-type images provided by the H07P14-containing DTTM device under an applied bias voltage of 0 V, detected at wavelengths of (c) 540, (d) 1,310 and (e) 1,550 nm. The images were constructed based on the existence or absence of a photocurrent during the point-by-point scanning of the DTTM device. Clear images of the capitalized letters ‘NTU’ were obtained, even though the incident power density was low; for example, 4.7 pW μm⁻² at a wavelength of 1,310 nm and 4.57 pW μm⁻² at a wavelength of 1,550 nm. The scale bar (b) and the pixel size (c–e) are 5 mm.