Owing to its suitable electronic bandgap, excellent air stability, and high carrier mobility at room temperature, low-dimensional bismuth oxyselenide (Bi 2 O 2 Se) has become attractive in the context of visible–near-infrared (VIS–NIR) detection. However, the high carrier concentration and bolometric effect of Bi 2 O 2 Se nanosheets are not conducive to reducing the dark current and improving the response speed, which hinders Bi 2 O 2 Se nanosheet-based photodetectors from achieving an optimal performance. In this study, a Bi 2 O 2 Se nanoribbon is controllably synthesized on a fluorophlogopite substrate by means of the chemical vapor deposition approach. Through the use of a Bi 2 O 2 Se nanoribbon structure and the application of a Schottky barrier between the Bi 2 O 2 Se and Au electrodes, a fast response and low noise photodetector is achieved. More specifically, the response times are 2.1 and 313 µs at 650 and 1550 nm, respectively, and the corresponding optimal detectivities are 3.28 × 10 13 and 8.07 × 10 9 Jones. Furthermore, the device reaches a −3 dB bandwidth of 81 kHz and exhibits a responsivity of 3.2 × 10 5 A W −1 at 650 nm under a bias of 5 V. This study provides new opportunities for the application of high-performance VIS–NIR photodetectors.
Binbin Wang,Huicheng Hu,Mohan Yuan,Ji Yang,Jing Liu,Liang Gao,Jianbing Zhang,Jiang Tang,Xinzheng Lan
HgTe nanocrystals (NCs) possess advantages including tunable infrared absorption spectra, solution processability, and low fabrication costs, offering new avenues for the advancement of next-generation infrared detectors. In spite of great synthetic advances, it remains essential to achieve customized synthesis of HgTe NCs in terms of industrial applications. Herein, by taking advantage of a high critical nucleation concentration of HgTe NCs, a continuous-dropwise (CD) synthetic approach that features the addition of the anion precursors in a feasible drop-by-drop fashion is demonstrated. The slow reaction dynamics enable size-customized synthesis of HgTe NCs with sharp band tails and wide absorption range fully covering the short- and mid-infrared regions. More importantly, the intrinsic advantages of CD process ensure high-uniformity and scale-up synthesis from batch to batch without compromising the excitonic features. The resultant HgTe nanocrystal photodetectors show a high room-temperature detectivity of 8.1 × 10 11 Jones at 1.7 µm cutoff absorption edge. This CD approach verifies a robust method for controlled synthesis of HgTe NCs and might have important implications for scale-up synthesis of other nanocrystal materials.
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