Search

Facing the future development trend of miniaturization and intelligence of electronic devices, solar‐blind photodetectors based on ultrawide‐bandgap 2D semiconductors have the advantages of low dark current, and high signal‐to‐noise ratio, as well as the features of micro‐nanometer miniaturization and multi‐functionalization of 2D material devices, which have potential applications in the photoelectric sensor part of high‐performance machine vision systems. This study reports a 2D oxide semiconductor, AsSbO3, with an ultrawide bandgap (4.997 eV for monolayer and 4.4 eV for multilayer) to be used to fabricate highly selective solar‐blind UV photodetectors, of which the dark current as low as 100 fA and rejection ratio of UV‐C and UV‐A reaches 7.6 × 103. Under 239 nm incident light, the responsivity is 105 mA W−1 and the detectivity is 7.58 × 1012 Jones. Owing to the remarkable anisotropic crystal structure, AsSbO3 also shows significant linear dichroism and nonlinear optical properties. Finally, a simple machine vision system is simulated by combining the real‐time imaging function in solar‐blind UV with a convolutional neural network. This study enriches the material system of ultrawide‐bandgap 2D semiconductors and provides insight into the future development of high‐performance solar‐blind UV optoelectronic devices. [ABSTRACT FROM AUTHOR]

Facing the future development trend of miniaturization and intelligence of electronic devices, solar‐blind photodetectors based on ultrawide‐bandgap 2D semiconductors have the advantages of low dark current, and high signal‐to‐noise ratio, as well as the features of micro‐nanometer miniaturization and multi‐functionalization of 2D material devices, which have potential applications in the photoelectric sensor part of high‐performance machine vision systems. This study reports a 2D oxide semiconductor, AsSbO3, with an ultrawide bandgap (4.997 eV for monolayer and 4.4 eV for multilayer) to be used to fabricate highly selective solar‐blind UV photodetectors, of which the dark current as low as 100 fA and rejection ratio of UV‐C and UV‐A reaches 7.6 × 103. Under 239 nm incident light, the responsivity is 105 mA W−1 and the detectivity is 7.58 × 1012 Jones. Owing to the remarkable anisotropic crystal structure, AsSbO3 also shows significant linear dichroism and nonlinear optical properties. Finally, a simple machine vision system is simulated by combining the real‐time imaging function in solar‐blind UV with a convolutional neural network. This study enriches the material system of ultrawide‐bandgap 2D semiconductors and provides insight into the future development of high‐performance solar‐blind UV optoelectronic devices. [ABSTRACT FROM AUTHOR]

Low‐dimensional ultrawide bandgap semiconductors demonstrate great potential in fabricating solar‐blind ultraviolet photodetectors. However, the widespread use of detectors is still limited by the low responsivity, large noise, and dark current, and especially few detectors can fulfill the solar‐blind ultraviolet detection and the polarization dependence simultaneously. Herein, a polarization sensitive solar‐blind ultraviolet photodetector based on ultrathin KNb3O8 nanobelts synthesized via chemical vapor deposition growth, is reported. By selecting suitable substrate and tuning the growth temperature, the nonlayered KNb3O8 crystal is grown into the quasi‐1D ultrathin nanobelt with thickness in the range of 4.8–120 nm. Density functional theory calculations and experimental results indicate that the ultrathin KNb3O8 nanobelt possesses an ultrawide bandgap (4.15 eV) as well as unusual in‐plane structural anisotropy. Benefiting from the above features, the ultrathin KNb3O8 nanobelt‐based device exhibits superior photodetection performances with high responsivity (30 A W−1), high detectivity (5.95 × 1011 Jones), and ultralow dark current (7.1 × 10−15 A) in the solar‐blind ultraviolet region (230–280 nm). In addition, the KNb3O8 photodetector displays strong polarization sensitive photoresponse with a linear dichroic ratio of 1.62 at 254 nm. With these remarkable features, the ultrathin KNb3O8 nanobelt provides great opportunities for designing the next‐generation multifunctional solar‐blind ultraviolet optoelectronic devices. [ABSTRACT FROM AUTHOR]

AbstractDumbbell-shaped carbonate minerals are widely recognized as a distinctive morphology induced by microorganisms. Understanding their morphological evolution and growth mechanisms is essential for elucidating bacterial-mediated carbonate mineralization processes. In this study, we used the mineralizing bacterium Curvibacter sp. strain HJ-1 to induce the formation of dumbbell-shaped carbonate minerals within a rapid crystallization system with a Mg/Ca ratio = 5. A range of microscale analytical techniques, including scanning electron microscopy, focused ion beam, and transmission electron microscopy, were employed to systematically investigate the morphological changes and crystallographic orientation of these minerals. The results reveal that the formation process involves the aggregation of Ca-Mg nanoparticles at both ends of the structure, with bacterial cells acting as a template. These findings offer preliminary insights into the formation mechanisms of dumbbell-shaped minerals and provide a scientific basis for biogenic analysis of field samples. [ABSTRACT FROM AUTHOR]

In an article published in Advanced Functional Materials, researchers Xinghua Wang, Zhongming Wei, Juehan Yang, and their colleagues discuss the development of photodetectors based on AsSbO3 nanosheets. These nanosheets have an ultra-wide bandgap, allowing for highly selective and high-performance detection in the solar-blind ultraviolet band. Additionally, the AsSbO3 nanosheets exhibit linear dichroism and nonlinear optical properties due to their anisotropic crystal structure. This research has implications for machine vision applications. [Extracted from the article]

Solar-blind ultraviolet (UV) detection plays a critical role in imaging and communication due to its low-noise background, high signal-to-noise ratio, and strong anti-interference capabilities. Detecting the polarization state of UV light can enhance image information and expand the communication dimension. Although polarization detection is explored in visible and infrared light, and applied in fields such as astrophysics and submarine seismic wave detection, solar-blind UV polarization detection remains largely unreported. This is primarily due to the challenge of creating UV polarizers with high transmittance, high extinction ratio, and strong resistance to UV radiation. In this study, it is discovered that the space symmetry breaking of the β-Ga 2 O 3 's b-c plane results in a significant optical absorption dichroic ratio. Leveraging β-Ga 2 O 3 's high solar-blind UV response, a lensless solar-blind UV polarization-sensitive photodetector, circumventing the challenges associated with solar-blind UV polarizers is designed. This photodetector exhibits an exceptionally high intrinsic polarization ratio under 254 nm linearly polarized light, approximately two orders of magnitude higher than other reported nanomaterial-based polarization-sensitive photodetectors. Additionally, it demonstrates significant advantages in solar-blind UV imaging and light communication. This work introduces a novel strategy for solar-blind ultraviolet polarization detection and offers a promising approach for solar-blind light communication., (© 2024 Wiley‐VCH GmbH.)