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In this study, a solution method derived dual‐band photodetector (PD) based on silicon nanowires /PbS nanocrystalline film n–n heterojunction, which exhibits typical bias‐selectable spectral response in both near‐infrared (NIR) and short‐wave infrared (SWIR) bands, is presented. It is found that by adjusting the polarity of the bias voltage, the photoresponse of the device can be switched between three operation modes. The device exhibits high responsivities of 2100 mA W−1 at −0.15 V and 31 mA W−1 at 0 V, respectively, in the NIR region. Remarkably, the maximum responsivity and detectivity under 2000 nm illumination are determined as 290 mA W−1 and 2.4 × 1010 Jones, comparable to or even better than some PbS commercial PDs. The enhanced performance comes from the improved optical absorption and higher efficiency of charge separation and collection owing to the heterojunction geometry. It's also revealed that the bias‐controllable spectral response is attributed to the selectively transportation of photocarriers across the junction barrier. The study demonstrates the capability of detecting two distinct IR regions with the same pixel, which has great potential in future optoelectronic systems for IR imaging applications. [ABSTRACT FROM AUTHOR]

Face-centered cubic CuS nanowires with length of up to 50 μm and diameters in the range of 100-500 nm are synthesized on Si substrates through the chemical vapor deposition method using a mixed gas of Ar and H as the carrier gas under a chamber pressure of about 700 Torr. It was found that the growth of quasi 1D nanostructure followed a typical vapor-liquid-solid (VLS) mechanism in which the element Cu was reduced by H as the catalyst. The as-synthesized CuS nanowires exhibited typical p-type semiconducting characteristics with a conductivity of about 600 S cm and a hole mobility ( μ ) of about 72 cm V s. Further study reveals that p-CuS nanowires/n-Si heterojunction exhibits distinct rectifying characteristics with a turn-on voltage of ~0.6 V and a rectification ratio of ~300 at ±1 V in the dark and a pronounced photovoltaic behavior with an open circuit voltage ( V ) of 0.09 V and a short circuit current ( I ) of 65 nA when illuminated by the NIR light (790 nm, 0.35 mW cm), giving rise to a responsivity ( R) about 0.8 mA W and specific detectivity ( D*) 6.7 × 10 cm Hz W at zero bias, which suggests the potential of as-synthesized CuS nanowires applied in the field of self-driven NIR photodetector. [ABSTRACT FROM AUTHOR]

We report on the rational synthesis of one-dimensional Cu2-xSe nanowires (NWs) via a solution method. Electrical analysis of Cu2-xSe NWs based memory device exhibits a stable and reproducible bipolar resistive switching behavior with a low set voltage (0.3-0.6 V), which can enable the device to write and erase data efficiently. Remarkably, the memory device has a record conductance switching ratio of 108, much higher than other devices ever reported. At last, a conducting filaments model is introduced to account for the resistive switching behavior. The totality of this study suggests that the Cu2-xSe NWs are promising building blocks for fabricating high-performance and low-consumption nonvolatile memory devices. [ABSTRACT FROM AUTHOR]

We presented an attempt to modulate the electrical property of tellurium nanowires (TeNWs) via a surface charge transfer doping method. The TeNWs with length of several tens of micrometers and diameters of 20-50 nm were prepared by a simple hydrothermal method at 160 °C for 20 h. High-resolution transmission electron microscope image combined with selected area electron diffraction pattern shows the single-crystal nature and a growth direction along [001]. Electrical analysis of the individual TeNW-based field effect transistor before and after surface coating reveals that MoO and CuPc thin layer coating can greatly enhance both electrical conductivities and hole concentrations. Such a surface hole injection effect, according to the band energy alignment, can be attributed to the huge differences in work functions between TeNW and MoO/CuPc. Furthermore, the influence of the deposited layer on carrier mobility is strikingly different, which is believed to be due to the discrepancy in surface scattering upon surface coating. The results from this study provide an effective alternative for doping other semiconductor nanostructures. [ABSTRACT FROM AUTHOR]

Photodetection in the solar‐blind deep‐ultraviolet (DUV) regime (200–280 nm) has received significant attention for its many critical applications in military and civil areas. In this study, a vapor–solid synthesis technique for catalyst‐free growth of single‐crystalline β‐Ga2O3 nanowires is developed. A photodetector made of the nanowires is highly sensitive to 265 nm DUV illumination with excellent photoresponse performance. The performance parameters including Ilight/Idark ratio, responsivity, specific detectivity and response speed can attain ≈103, ≈233 A W−1, ≈8.16 × 1012 Jones, and 0.48/0.04 s, respectively. Additionally, the detector has an abrupt response cutoff wavelength at ≈290 nm with a reasonable DUV/visible (250–405 nm) rejection ratio exceeding 102. It is also found that the device can operate properly at a large applied bias of 200 V with the responsivity being enhanced to as high as ≈1680 A W−1. Moreover, such a nanowires‐based photodetector can function as a DUV light image sensor with a reasonable spatial resolution. Holding the above advantages, the present DUV photodetector based on catalyst‐free grown β‐Ga2O3 nanowires possesses huge possibility for application in future DUV optoelectronics. [ABSTRACT FROM AUTHOR]

Combining both 1D geometry and the features of hybrid perovskite materials, perovskite micro/nanowires have recently attracted particular attention for a variety of optoelectronic device applications. Herein, by taking advantage of the strong built‐in potential induced by asymmetric contact with varied work functions, highly sensitive visible photodetectors based on a CH3NH3PbI3 microwire array that display pronounced photovoltaic activities are reported. These photodetectors afford the capability to work without an external power supply. A representative detector with Au/Ag electrodes achieves a reasonable responsivity of 161.1 mA W−1 with a fast response speed of 13.8/16.1 µs under 520 nm illumination at zero bias. In addition, such a device is also characterized by an ultralow dark current of tens of femtoamps, enabling a high specific detectivity of 1.3 × 1012 Jones. Furthermore, a flexible photodetector is successfully prepared, which shows comparable photoresponse performance and outstanding flexibility and bending durability. Given the good device performance and simple device geometry, the present self‐driven photodetectors hold great promise for future highly sensitive and low‐energy‐consumption photodetection systems. [ABSTRACT FROM AUTHOR]