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In this work, we report on the synthesis of InSe nanobelts through a catalyst-free chemical vapor deposition (CVD) growth approach. A remarkable blue shift of the peak photoresponse was observed when the thickness of the InSe nanobelt decreases from 562 to 165 nm. Silvaco Technology Computer Aided Design (TCAD) simulation reveals that such a shift in spectral response should be ascribed to the wavelength-dependent absorption coefficient of InSe, for which incident light with shorter wavelengths will be absorbed near the surface, while light with longer wavelengths will have a greater penetration depth, leading to a red shift of the absorption edge for thicker nanobelt devices. Considering the above theory, three kinds of photodetectors sensitive to blue (450 nm), green (530 nm), and red (660 nm) incident light were achieved by tailoring the thickness of the nanobelts, which can enable the spectral reconstruction of a purple "H" pattern, suggesting the potential application of 2D layered semiconductors in full-color imaging.

In this work, we present the assembly of a γ-In2Se3/GaAs heterostructure-based photodetector linear array composed of 1 × 10 device units. The layered γ-In2Se3 films with a well-defined pattern are deposited directly onto a planar GaAs substrate via radio-frequency (RF) magnetron sputtering deposition assisted by a pre-photolithography process. The as-fabricated heterojunction exhibits an apparent photovoltaic effect, which endows the device with a function to operate as a self-driven photodetector. The critical photoresponse performance parameters in terms of the Ilight/Idark ratio, responsivity (R), specific detectivity (D*) and response speed can reach 1.29 × 104, 0.25 A W−1, 7.34 × 1012 Jones and 23.6/146.7 μs (rise/fall times), respectively, upon 660 nm light irradiation at 0 V. What is more, further device evaluation reveals that the photodetector array shows good uniformity with a minor unit-to-unit variation. The above merits endow the photodetector array with the ability to monitor a moving optical signal and to record an “E” image produced by visible illumination. It is believed that the present photodetector array is very promising for some optoelectronic purposes such as real-time light trajectory tracking and visible light image sensing applications.

Graphene quantum dots (GQDs), with stable photoluminescence (PL) and electrocatalytic activity, have potential application in sensor field. Herein, a facile novel electrochemiluminescence (ECL) sensor based on GQDs and glassy carbon electrode (GCE) was developed to detect Butyl hydroxy anisd (BHA) and Gallic acid. The optimization of ECL detection conditions were investigated. Hence, the sensor exhibited relatively strong luminescence intensity even without the modification of the GCE, which make this sensor system easy to implement. The developed sensor exhibited a linear response ranging from 5 to 160 μM under the optimum conditions. The method displayed the advantages of high sensitivity, good selectivity, wide linear range, low detection limit and fine reproducibility. Moreover, the practicability of the ECL sensing platform in real water samples had shown the satisfactory results, which holds a great potential in the field of pharmaceutical analysis.

A γ-In2Se3/Si heterostructure phototransistor with a broadened photoresponse has been developed, presenting a responsivity, specific detectivity and response speed of 10.24 A W−1, 8.63 × 1012 Jones and 0.76/0.85 ms (rise time/fall time) at 450 nm, respectively. The high responsivity could be attributed to the depressed dark current of the γ-In2Se3 nanofilm and the high gain arising from the gating effect of the phototransistor. Further analysis reveals that the relatively high responsivity and fast response speed facilitate the application of the device in real-time and accurate health monitoring, such as heart rate detection.