Fig. 2: Unpolarized broadband optoelectronic responses for Te nanoflake device.

a, b Photocurrent for the infrared range: 2.3 and 3.0 μm illumination under 300 K temperature, respectively, as a function of laser power and drain bias. c, d Photocurrent for the infrared range: 2.3 and 3.0 μm illumination under 77 K temperature, respectively, as a function of laser power and drain bias. e, f Pseudo-color mapping figures for R and D_M*, as a function of laser power and wavelength at room temperature (300 K). The drain bias is fixed at 1.0 V, and the gate bias is 0 V, the results are in accordance with the absorption characters of Te and indicate the high performance of Te nanoflake for NIR and MIR range. g–i Photoresponses under different gate biases. The drain bias is 1.0 V, and the incident wavelength is 3.0 μm. Panels (g) and (h) show the transfer curves under different incident powers and the dark state, and (i) shows the net photocurrents under different illumination powers based on current data in (g) and (h). The maximum photocurrent is achieved at the neutral point of ∼5.9 V gate bias for all the incident powers. j The photocurrent distribution in the Te channel under 0.637 and 0.83 μm illumination at 1.0 V drain bias and 0 V gate bias, with the photocurrent generated at the channel/electrode interface. The inset shows the image of the Te device with laser spot size of ∼3 μm, scale bar, 10 μm. k, l Pseudo-color mapping figures for R and D_M*, as a function of laser power and wavelength at 77 K. The drain bias is fixed at 1.0 V, and the gate bias is 0 V, much higher device performance is achieved under low temperature. m Stability verification, the photocurrent and dark current are measured at 1.0 V drain bias and 0 V gate bias, the selected illumination wavelength is 3.0 μm, with the laser power of 6.0 mW. The performance at five selected point-in-time: as fabricated, 1 day later, 7 days later, 1 month later, 3 months later, are not degraded, which indicates that the Te-based device is very stable at ambient conditions for a long time. n, o R and D_M* for the measured range marked by shaded rectangles in (m), the high performance of Te is preserved for a long time.