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The quest for solar-blind photodetectors with outstanding optoelectronic properties and weak signals detection capability is essential for their applications in the field of imaging, communication, warning, etc. To date, Ga2O3 has demonstrated potential for high-performance solar-blind photodetectors. However, the performance usually decays superlinearly at low light intensities due to carrier-trapping effect, which limits the weak signal detection capability of Ga2O3 photodetectors. Herein, a Ga2O3 solar-blind photodetector with ultra-thin absorbing medium has been designed to restrain trapping of photo-generated carriers during the transporting process by shortening the carrier transport distance. Meanwhile, multiple-beam interference is employed to enhance the absorption efficiency of the Ga2O3 layer using an Al/Al2O3/Ga2O3 structure. Based on the ultra-thin absorbing medium with enhanced absorption efficiency, a 7 × 7 flexible photodetector array is developed, and the detectivity can reach 1.7 × 1015 Jones, which is among the best values ever reported for Ga2O3 photodetectors. Notably, the performance of the photodetector decays little as the illumination intensity is as weak as 5 nW/cm2, revealing the capacity to detect ultra-weak signals. In addition, the flexible photodetector array can execute the functions of imaging, spatial distribution of light source intensity, real-time light trajectory detection, etc. Our results may provide a route to high-performance solar-blind photodetectors for ultra-weak light detection. [ABSTRACT FROM AUTHOR]

Solar‐blind detectors play important roles in military and civilian affairs, due to their high signal‐to‐noise ratio and low‐false alarm rate. In recent years, wide‐bandgap semiconductor‐based solar‐blind photodetectors have been studied extensively. However, very little attention has been paid to position detection of solar‐blind light. Herein, a solar‐blind position‐sensitive detector (PSD) is fabricated from β‐Ga2O3/polycrystalline diamond heterojunctions. The solar‐blind PSD shows good solar‐blind response characteristics. In addition, the output signals of the PSD are dependent on the position of the solar‐blind light spot, which can be utilized to realize position detection of solar‐blind signals. [ABSTRACT FROM AUTHOR]

Monoclinic gallium oxide (β-Ga2O3) has drawn much attention in solar-blind detection because of its unique characteristics such as good thermal and chemical stability, intrinsic visible/solar blind, high breakdown electric field, etc. However, the relatively slow response hinders the actual applications of β-Ga2O3 photodetectors. In this work, AlN/β-Ga2O3 heterojunction photodetectors with a fast response speed of 320 ns have been developed. Moreover, the AlN/β-Ga2O3 heterojunction photodetector can work at 0 V with a responsivity of 7.0 mA W−1 and a detectivity of 1.25 × 1013 cm Hz1/2W−1. The results reported in this work indicate that AlN/β-Ga2O3 heterojunctions are feasible for solar-blind photodetectors with fast response and high sensitivity. [ABSTRACT FROM AUTHOR]

In this work, high-performance solar-blind photodetectors based on MXenes–β-Ga2O3 Schottky junctions have been developed by utilizing transparent conductive MXenes as the Schottky electrode of β-Ga2O3. Due to the high MXenes–β-Ga2O3 Schottky barrier, the photodetectors exhibit a rectification ratio as high as over 103 at ±2 V. At zero bias, the photodiodes show a responsivity of 12.2 mA W−1 at 248 nm and a detectivity of 6.1 × 1012 Jones, which are among the best values for β-Ga2O3-based solar-blind photodetectors working at zero bias. In addition, the Schottky photodiodes show a fast response speed with a rise time of 8 μs and decay time of 131 μs. Our results indicate that MXenes may be promising candidate for use as transparent conductive electrodes for UV optoelectronics. [ABSTRACT FROM AUTHOR]

MicroRNA (miR)-106b~25 cluster regulates bypass of doxorubicin and γ-radiation induced senescence by downregulation of the E-cadherin transcriptional activator EP300. We asked whether upregulation of miR-106~25 cluster generates cells with a truly multidrug resistant (MDR) phenotype and whether this is due to upregulation of the ATP-binding cassette (ABC) transporter P-glycoprotein. We used minimally transformed mammary epithelial breast cancer cells (MTMECs) in which the miR-106b~25 cluster was experimentally upregulated by lentiviral transfection or in which hairpins targeting either EP300 or E-cadherin mRNAs have been expressed with lentiviruses. We find that overexpression of miR-106b~25 cluster led to the generation of MDR MTMECs (resistant to etoposide, colchicine and paclitaxel). Paclitaxel resistance was also studied after experimental downregulation of EP300 or E-cadherin. However none of these cells overexpressed P-glycoprotein or where able to efflux a fluorescent derivative of paclitaxel, making this phenotype drug-transporter independent. Paclitaxel treatment in MTMECs led to an increase in early apoptotic cells (Annexin V-positive), activation of caspase-9 and increase in the proportion of cells at the G2/M phase of the cell cycle. However, MTMEC overexpressing miR-106b~25 cluster, or with EP300 or E-cadherin downregulated, showed less activation of apoptosis, caspase-9 and caspase-3/-7 activities. Thus, miR-106b~25 cluster controls transporter-independent MDR by apoptosis evasion via downregulation of EP300.