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Self‐driven broadband photodetectors have wide applications in the fields of biomedicine, remote sensing, rescue, and mineral exploration with advantages of energy conservation and multiband detection. However, most present broadband photodetectors are suffering from a fast degradation of photoresponsivity in ultraviolet (UV) region. To resolve it, a self‐driven broadband photodetector is proposed based on mixed‐dimensional 2D PtSe2/3D amorphous Ga2O3 (a‐Ga2O3) heterojunction considering the high UV responsivity of a‐Ga2O3 thin film. 2D PtSe2 is obtained on a‐Ga2O3 thin film by a simple selenization method directly. The responsivity of the completed device in UV region is about 14 and 172 times higher than that in visible and NIR regions, respectively. In addition, benefiting from the excellent built‐in electric field at the heterojunction and high carrier mobility of 2D PtSe2, photogenerated electron–hole pairs can be rapidly separated. As a result, its rise time (9.36 ms) and decay time (11.27 ms) are much faster than those of the current a‐Ga2O3‐based self‐driven photodetectors (≈100–1000 ms). This work provides a novel building block via a facile strategy for the further development of high‐performance, low‐cost, and energy‐efficient broadband photodetectors. [ABSTRACT FROM AUTHOR]

Organic‐inorganic hybrid perovskites are promising candidates for direct X‐ray detection and imaging. The relatively high dark current in perovskite single crystals (SCs) is a major limiting factor hindering the pursuit of performance and stability enhancement. In this study, the contribution of dark current is disentangled from electronic (σe) and ionic conductivity (σi) and shows that the high σi dominates the dark current of MAPbBr3 SCs. A multilayer heterojunctions passivation strategy is developed that suppresses not only the σi by two orders of magnitude but also σe by a factor of 1.6. The multilayer heterojunctions passivate the halide vacancy defects and increase the electron and hole injection barrier by inducing surface p‐type doping of MAPbBr3. This enables the MAPbBr3 SC X‐ray detectors to obtain a high sensitivity of 19 370 µC Gyair−1 cm−2 under a high electric field of 100 V cm−1, a record high sensitivity for bromine self‐powered devices, and a low detection limit of 42.3 nGyair s−1. The unencapsulated detectors demonstrate a stable baseline after storage for 210 days and outstanding operational stability upon irradiation with an accumulated dose of up to 1944 mGyair. [ABSTRACT FROM AUTHOR]

Developing optoelectronic synaptic devices with low energy consumption is of critical importance for neuromorphic computing and visualization systems. In this work, amorphous‐Ga2O3 (a‐Ga2O3) is adopted to realize a low‐power optoelectronic synapse considering its distinguished features of ultra‐wide bandgap, high responsiveness to light stimulation, and strong persistent photoconductivity effect. The basic synaptic functions such as short‐term plasticity (STP) and long‐term plasticity (LTP) have been successfully mimicked. A noise suppression capability is achieved as well, similar to the visual cells. Strikingly, the total energy consumption for triggering an LTP synaptic event is only 136 fJ, approaching the one of a biological synapse. The underlying mechanism for the a‐Ga2O3 synaptic performance is explored with a combined research of X‐ray photoelectron spectroscopy, Kelvin probe force microscopy, electric tests, and Technology Computer‐Aided Design simulations. The consistent results suggest the key role of the synergetic modulation effect of optical and electric fields on the dynamic behaviors of oxygen vacancy (VO) defects. This work indicates the potential applications of a‐Ga2O3 in low‐power optoelectronic synapses. [ABSTRACT FROM AUTHOR]

Background: Studies have found conflicting results concerning the left ventricular (LV) myocardial deformation properties in patients with normally functioning bicuspid aortic valves (BAVs). Whether the remodeling process of LV occurs independently in patients with BAV is a matter of debate. Method: We searched PubMed, Embase, Cochrane library, and Web of Science for cohort studies aiming to assess LV function in adults with isolated BAV compared with tricuspid aortic valve (TAV) controls. Standard mean difference (SMD) was calculated from random‐effects meta‐analyses. Results: Eight cohort studies were included. There were significantly lower global longitudinal strain (GLS), global radial strain (GRS), global circumferential strain (GCS) in BAV than in TAV controls (GLS: SMD = 0.64, 95% CI: 0.35 to 0.92, P <.0001; GRS: SMD = −0.71, 95% CI: −1.09 to −0.32, P =.0003; GCS: SMD = 0.70, 95% CI: 0.41 to 0.98, P <.00001) and significantly higher left atrial volume index (LAVI) and E/e' in BAV than in TAV controls (LAVI: SMD = 0.50, 95% Cl: 0.12 to 0.88, P =.01; E/e': SMD = 0.54, 95% CI: 0.30 to 0.77, P <.00001). There was significantly higher Left ventricular mass index（LVMI） in BAV than in TAV controls (SMD = 0.51, 95% CI: 0.24 to 0.79, P =.0003). Left ventricular ejection fraction (LVEF) was not significantly different between BAV patients and TAV controls (SMD = 0.05, 95% CI: −0.16 to 0.26, P =.63). Conclusion: The impairment of LV myocardial mechanics, including LV systolic, diastolic dysfunction and LV hypertrophy, is present in patients with normally functioning BAV. This might support the hypothesis that BAV is not only a valvular disease but also a myocardial disease. [ABSTRACT FROM AUTHOR]

This work reports an integrated flexible deep ultraviolet (UV) photodetection system hosting an amorphous Ga2O3 (a‐Ga2O3) photodetector (PD) and an energy harvesting component including a receiving electrode and a full‐wave rectifier. An alternating signal is induced by the coupling of human body with environmental electromagnetic radiation through human hand's contact with the receiving electrode. The signal is subsequently converted into direct current (DC) by the rectifier which is composed of four thin‐film diodes with high rectification ratio (≈106) and fast response time (rising time ≈240 µs and falling time ≈680 µs). Driven by the DC output, the a‐Ga2O3 PD achieves a photoresponsivity of 0.10 A W−1 and a detectivity of 2.24 × 1011 Jones under 254 nm UV illumination. The integrated flexible a‐Ga2O3 UV PD manifests a repeatable and pleasurable response behavior with a bending radius of 15 mm, providing a new paradigm for utilizing the environmental energy as the power source in wearable electronics. [ABSTRACT FROM AUTHOR]

Deep ultraviolet (UV) photodetectors have wide applications both in civil and military fields. Many materials have been explored to realize deep UV photodetection. Amorphous gallium oxide (a‐GaOx), as a member of transparent amorphous oxide semiconductors (TAOSs), has attracted a great deal of attention due to its ultrawide bandgap and scalable synthesis at room temperature. Plenty of researches have been focused on this topic in recent years. Herein, the latest progresses in the preparation methods of a‐GaOx using radio‐frequency sputtering, pulsed laser deposition, atomic layer deposition, and other deposition techniques are summarized. Dependence of the stoichiometry, crystallinity, optical, electrical, and morphological properties on different preparation parameters and doping/alloying elements is tentatively discussed, as well as those deep UV photodetectors based on a‐GaOx and related thin films. Finally, a short summary with further possible investigations is provided for a better understanding and development of a‐GaOx materials and photodetectors. [ABSTRACT FROM AUTHOR]

A three‐terminal thin‐film transistor (TFT) architecture is essential for photodetectors to reach a good balance between high responsivity and fast response speed. Bottom‐gate amorphous Ga2O3 (a‐Ga2O3) TFTs are fabricated to boost their UV photodetection properties. During the device fabrication process, a simple chemical‐etching solution with the advantages of easy operation, low cost, and compatibility with traditional lithography process, is developed to selectively etch a‐Ga2O3 films. The a‐Ga2O3 channel etched device on Si manifests an effective suppression of the commonly observed gate leakage current. Meanwhile, a patterned a‐Ga2O3 TFT on quartz shows an excellent n‐type TFT performance with an on/off ratio as high as ≈107. It is further applied as a phototransistor, to diminish the persistent photoconductivity (PPC) effect while keeping a high responsivity (R) as well. Under the 254 nm UV illumination, the a‐Ga2O3 phototransistor demonstrates a high light‐to‐dark ratio of 5 × 107, a high responsivity of 5.67 × 103 A W−1, and a high detectivity of 1.87 × 1015 Jones. Remarkably, the PPC phenomenon in a‐Ga2O3 UV phototransistors is effectively suppressed by applying a positive gate pulse, which greatly shortens the decay time to 5 ms and offers a‐Ga2O3 possible inroads into imaging applications. [ABSTRACT FROM AUTHOR]

In this work, the optical properties of defects coupled with surface plasmons (SPs) in gallium‐doped ZnO (ZnO:Ga) grown by molecular beam epitaxy (MBE) have been explored. The photoluminescence intensity is enhanced by up to 4.9 times as a result of SPs coupling by decorating the sample with silver nanospheres (Ag NSs), with a fast plasmonic decay lifetime of 0.1 ns compared with the defect‐assisted carrier recombination lifetime of 3.77 ns in the as‐grown sample. The enhanced emission intensity depends on the plasmonic modes determined by the diameter of Ag NSs, verified by power‐dependent photoluminescence measurements. Confocal mapping reveals that the plasmonic “hot‐spots”, that is, enhanced emission around the Ag NSs, exhibit a highly optical stability with reduced photoluminescence blinking. This work demonstrates that a defect coupled with SPs in ZnO is a promising high‐efficiency emitter for applications in nanophotonics. [ABSTRACT FROM AUTHOR]

Integration of oxides with Si opens promising opportunities for novel multifunctional devices and new applications. To optimize the device performances through the hybrid integration, keeping the oxide/Si interface abrupt is critically important and challenging due to the seemingly unavoidable formation of amorphous SiO x or silicide interfacial layers. Here, we report an interface-engineering approach to this issue by molecular beam epitaxy. A BeO thin layer (∼5 nm) was deposited on Si (111) surface using a two-step process of Be deposition and oxidation. The initially formed BeO served as a template for subsequent homo-epitaxial growth of a 10-nm crystalline BeO layer. The well-defined interface between BeO and Si is clearly discerned by high-resolution transmission electron microscopy, implying the role of crystalline BeO as a barrier layer against oxygen atoms' diffusion. High-resolution X-ray photoelectron spectroscopy further confirmed that the combined BeO layers sufficiently protect the Si surface from oxidation. A bottom-gate enhancement-mode thin film transistor was established on a ZnO (130 nm)/BeO (70 nm)/Si architecture, where BeO was functionalized both as a diffusion barrier and as a high- k gate insulator. It indicates that this methodology can be potentially extended to hybrid integration of other technologically important crystalline oxides with Si infrastructures. [ABSTRACT FROM AUTHOR]