III-V semiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices. However, solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world. By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires, new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials. Herein, we combine high-crystal-quality III-nitride nanowires with amorphous molybdenum sulfides (a-MoS) to construct III-nitride/a-MoS core-shell nanostructures. Upon light illumination, such nanostructures exhibit striking spectrally distinctive photodetection characteristic in photoelectrochemical environment, demonstrating a negative photoresponsivity of -100.42 mA W under 254 nm illumination, and a positive photoresponsivity of 29.5 mA W under 365 nm illumination. Density functional theory calculations reveal that the successful surface modification of the nanowires via a-MoS decoration accelerates the reaction process at the electrolyte/nanowire interface, leading to the generation of opposite photocurrent signals under different photon illumination. Most importantly, such polarity-switchable photoconductivity can be further tuned for multiple wavelength bands photodetection by simply adjusting the surrounding environment and/or tailoring the nanowire composition, showing great promise to build light-wavelength controllable sensing devices in the future.
Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
Anomalous negative phototransistors have emerged as a distinct research area, characterized by a decrease in channel current under light illumination. Recently, their potential applications have been expanded beyond photodetection. Despite the considerable attention given to negative phototransistors, negative photoconductance (NPC) in particular remains relatively unexplored, with limited research advancements as compared to well-established positive phototransistors.
III-V semiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices. However, solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world. By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires, new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials.
SnSe field-effect transistor was fabricated based on exfoliated few-layered SnSe flake, and its electrical and photoelectric properties have been investigated in detail. With the help of a drop of de-ionized (DI) water, the SnSe FET can achieve an on/off ratio as high as ~ 10 within 1 V bias, which is ever extremely difficult for SnSe due to its ultrahigh carrier density (10/cm). Moreover, the subthreshold swing and mobility are both improved to ∼ 62 mV/decade and ~ 127 cm V s at 300 K, which results from the efficient screening by the liquid dielectric gate.
Plasmon-induced hot-electron generation is gaining attention for its potential in optoelectronics, photovoltaics, and green chemistry, involving hot electrons from metal nanoparticles and nanostructures.
Researchers have developed a dual-plasmon device that generates hot electrons from both localized and propagating sources to achieve controllable photoconductivity based on wavelength.
The device's photocurrent polarity can be adjusted across the visible spectrum, opening avenues for applications in biosensing, long-distance communication, and photoconversion.
