Figure 4. Electrical characterization, photodetector array and its packaged devices of patterned 2D crystals.

(a,b) Photograph and OM image of In₂Se₃ photodetector arrays on the transparent and flexible mica substrate. Seven channels were labelled from 1 to 7, defined by the same source. Scale bar in a, 1 cm. Scale bar in b, 20 μm. (c) Photoresponse of multiple In₂Se₃ photodetector channels. Source–drain voltage (V_SD)=0.1 V, light power density: 4 mW cm⁻². (d) Current–voltage (I_SD–V_SD) curves of the individual device in the dark and under different illumination intensities with a 633-nm defocused laser. (e) Dependence of photoresponse on different illumination intensities and bias voltage. The device exhibits a photoresponsivity of 1,650 A W⁻¹ under bias of 5 V for an illumination power intensity of 622 nW cm⁻² and a device area of 40 μm². (f) Statistic distribution of photoresponsivity of 18 devices based on the semiconducting In₂Se₃ crystal array on mica substrates. (g) Schematic of device packaging, the photograph of packaged device and its OM image. Electrodes and In₂Se₃ were pressed together by a lamination process. Electrodes (Ti/Au, 10 nm/40 nm) were defined onto the PET films by photolithography and thermal evaporation. Scale bar, 20 μm. (h) Photoresponse characterization of the packaged device. Inset: time-dependent photocurrent response of the packaged In₂Se₃ device at a bias voltage of 5 V. (i) Current as a function of bending cycles (before/after bending to a 10 mm radius) of the packaged In₂Se₃ devices on mica protected by PET with the laser on or off at a bias voltage of 5 V.