776 research outputs found
High-performance near-infrared photodetector based on nano-layered MoSe2
In recent years, the integration of two-dimensional (2D) nanomaterials, especially transition metal chalcogendies (TMCs) and dichalcogendies (TMDCs), into electronic devices have been extensively studied owing to their exceptional physical properties such as high transparency, strong photoluminescence, and tunable bandgap depending on the number of layers. Herein, we report the optoelectronic properties of few-layered MoSe2-based backgated phototransistor used for photodetection. The photoresponsivity could be easily controlled to reach a maximum value of 238 AW–1 under near-infrared light excitation, achieving a high specific detectivity D∗ = 7.6×10** cmHz*/1W3* . Few-layered MoSe2 exhibited excellent optoelectronic properties as compared with those reported previously for multilayered 2D material-based photodetectors, indicating that our device is one of the best high-performance nanoscale near-infrared photodetector based multilayered two-dimensional materials
Black phosphorus: narrow gap, wide applications
The recent isolation of atomically thin black phosphorus by mechanical
exfoliation of bulk layered crystals has triggered an unprecedented interest,
even higher than that raised by the first works on graphene and other
two-dimensional, in the nanoscience and nanotechnology community. In this
Perspective we critically analyze the reasons behind the surge of experimental
and theoretical works on this novel two-dimensional material. We believe that
the fact that black phosphorus band gap value spans over a wide range of the
electromagnetic spectrum that was not covered by any other two-dimensional
material isolated to date (with remarkable industrial interest such as thermal
imaging, thermoelectrics, fiber optics communication, photovoltaics, etc), its
high carrier mobility, its ambipolar field-effect and its rather unusual
in-plane anisotropy drew the attention of the scientific community towards this
two-dimensional material. Here we also review the current advances, the future
directions and the challenges in this young research field.Comment: Updated version of the perspective article about black phosphorus,
including all the feedback received from arXiv users + reviewer
Photo-FETs: phototransistors enabled by 2D and 0D nanomaterials
The large diversity of applications in our daily lives that rely on photodetection technology requires photodetectors with distinct properties. The choice of an adequate photodetecting system depends on its application, where aspects such as spectral selectivity, speed, and sensitivity play a critical role. High-sensitivity photodetection covering a large spectral range from the UV to IR is dominated by photodiodes. To overcome existing limitations in sensitivity and cost of state-of-the-art systems, new device architectures and material systems are needed with low-cost fabrication and high performance. Low-dimensional nanomaterials (0D, 1D, 2D) are promising candidates with many unique electrical and optical properties and additional functionalities such as flexibility and transparency. In this Perspective, the physical mechanism of photo-FETs (field-effect transistors) is described and recent advances in the field of low-dimensional photo-FETs and hybrids thereof are discussed. Several requirements for the channel material are addressed in view of the photon absorption and carrier transport process, and a fundamental trade-off between them is pointed out for single-material-based devices. We further clarify how hybrid devices, consisting of an ultrathin channel sensitized with strongly absorbing semiconductors, can circumvent these limitations and lead to a new generation of highly sensitive photodetectors. Recent advances in the development of sensitized low-dimensional photo-FETs are discussed, and several promising future directions for their application in high-sensitivity photodetection are proposed.Peer ReviewedPostprint (author's final draft
Electrical Control of Linear Dichroism in Black Phosphorus from the Visible to Mid-Infrared
The incorporation of electrically tunable materials into photonic structures
such as waveguides and metasurfaces enables dynamic control of light
propagation by an applied potential. While many materials have been shown to
exhibit electrically tunable permittivity and dispersion, including transparent
conducting oxides (TCOs) and III-V semiconductors and quantum wells, these
materials are all optically isotropic in the propagation plane. In this work,
we report the first known example of electrically tunable linear dichroism,
observed here in few-layer black phosphorus (BP), which is a promising
candidate for multi-functional, broadband, tunable photonic elements. We
measure active modulation of the linear dichroism from the mid-infrared to
visible frequency range, which is driven by anisotropic quantum-confined Stark
and Burstein-Moss effects, and field-induced forbidden-to-allowed optical
transitions. Moreover, we observe high BP absorption modulation strengths,
approaching unity for certain thicknesses and photon energies
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