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SEM Image of Ordered Array of V2O5 Nanowires
Photoelectric detection plays an important role in medical diagnosis, biochemical analysis, and environmental protection, and has a wide range of application prospects. Improving the detector's responsiveness, signal-to-noise ratio, response speed, and practicality are goals that researchers have been striving for. The researchers of the research group carried out a series of work around this goal, and made new progress in the preparation and performance optimization of nanomaterials for photodetection: preparation of ordered arrays of vanadium oxide nanowires, vanadium dioxide/carbon, respectively. Nanotube composite films, ordered arrays of germanium (Te) nanowires, and nanowires of lead telluride (PbTe) lattice structures were constructed, and prototype detectors were constructed based on the above materials. Relevant studies have shown that crystallized nanowires can effectively reduce the influence of interfaces and defects in the electron transport and make the electron transport channels smoother. The performance of photodetectors based on nanowires arranged along the rows of nanowires and grid structures is significant. improve.
Successful preparation of large-scale highly ordered vanadium oxide nanowire arrays At present, the research on the photoelectric properties of nanomaterials is mostly focused on single nanowires. Others' studies have shown that the optical properties of single nanowires are better than that of conventional commercial photoelectric detection. Device. However, since the effective light area of ​​a single nanowire is small, the resulting photocurrent is very small and requires a very precise instrument to measure. If a single nanowire is arranged to form an ordered array, it can not only exert the advantages of nano-material photoelectric properties, but also maximize the effective illumination area. Based on this, the research group Fu Wenbiao used hydrothermal method to prepare vanadium oxide nanowires with high crystallinity and few defects, and succeeded in preparing large-scale and highly ordered vanadium oxide nanowire arrays. The array size can reach the order of square millimeters. The prototype V2O5 photodetector device exhibits high detection performance at an incident wavelength of 450 nm, with a device responsivity of 160.3 mA/W, a detection rate of 6.5×108 Jones, and a response time of 17 to 12 ms (J. Mater). Chem. C, 2017, 5(6): 1471-1478). This work is of great significance in advancing the fabrication of array structures and applications in optoelectronic devices and other fields.
V2O nanowire array photodetector performance
The prepared vanadium dioxide/carbon nanotube composite film has a strong infrared photoelectric response thermal infrared detector which utilizes the thermal effect of infrared radiation to cause the temperature change of the detector to realize detection, compared to the photon type infrared detector, the heat is The advantage of the infrared detector is that it has nothing to do with the incident light wavelength, can work at room temperature, and has a low cost. VO2(M) has a large temperature resistivity. Carbon nanotubes have the characteristics of small heat capacity and high thermal conductivity. Combine VO2(M) with carbon nanotubes to form a double-layered composite film. This will make full use of the advantages of both, and transfer the heat absorbed by the carbon nanotubes to VO2(M) rapidly, maximizing the amount of infrared light. Photoelectric characteristics. They cooperated with Professor Jiang Kaili's research group of the Nanotechnology Research Center of Tsinghua University to prepare a composite film of carbon nanotubes and VO2. This VO2(M)/carbon nanotube double-layer composite film has significantly higher infrared photoelectric response characteristics than a pure VO2 film (J. Mater. Sci., DOI: 10.1007/s10853-017-0959-z).
Preparation of VO2(M)/Carbon Nanotubes Composite Film and Its Infrared Detection Curve
碲 Nanowire ordered array infrared detector research progress is a narrow bandgap semiconductor material with a band gap of about 0.35eV at room temperature and excellent photoelectric properties. Compared with nanocrystalline films with a large number of interfaces, the single crystal nanowires have few grain boundaries and have weak scattering effects on photogenerated carriers. Therefore, they exhibit good photoelectric properties and are currently a hot topic of research. As mentioned earlier, the assembly of individual nanowires in a row to form an ordered array will allow the nanomaterials to take advantage of their good optoelectronic properties and maximize the effective light area.
Zhong Binnian et al. prepared uniform size germanium nanowires and assembled large-area ordered nanowire arrays. An infrared photodetector prototype device based on this large-area ordered array of germanium nanowires exhibits good infrared response characteristics. Compared with unordered germanium nanowire devices, its response rate is greatly improved and its response time is shortened. This work reveals the great advantages of ordered array structures in photodetection. This work was published in Phys. Chem. Chem. Phys., 2016, 18(48): 32691-32696.
PCCP Magazine Volume 18 Number 48 Back cover
Advances in performance research of infrared detection of lead telluride nanowires based on lead telluride (PbTe) infrared detector can cover the mid- far infrared wavelength, low detection noise, high quantum efficiency, high sensitivity, has a wide range of applications in infrared detection prospect. At present, PbTe infrared detectors mainly exist in the form of thin films composed of nano-particles, but the interfaces between the nano-particles in the thin films may hinder the transport of electrons, resulting in a decrease in the detector performance. The MSM photodetector is a metal-semiconductor-metal contact photovoltaic detector that can be viewed as a pair of back-to-back Schottky barrier diodes. The detector's dark current is usually very small. The research group Gong Xinxin combined the advantages of single crystal nanowires and MSM type structures to construct a prototype infrared detector of MSM structure of PbTe single crystal nanowires. Studies have shown that this detector prototype device has good cycle stability and response times in the order of milliseconds, much faster than the films composed of particles (see Appl. Surf. Sci., 2017, 407: 7-11).
Optical curve and response time curve of PbTe nanowire infrared detector
The above work has been funded by the National Major Scientific Research Project and several National Natural Science Foundation projects.
(Original title: Hefei Research Institute made a series of progress in photoelectric detection research)
Photoelectric Detector Research Institute of Hefei Institute of Chinese Academy of Sciences Receives Breakthrough
[China Instrument Network Instrument R&D] Recently, Fei Guangtao, a researcher at the Institute of Solid State Physics of the Chinese Academy of Sciences' Hefei Institute of Physical Physics, made a series of progresses in the photoelectric detection of nanomaterials.
Related research work was published in Phys. Chem. Chem. Phys., 2016, 18(48): 32691-32696, J. Mater. Chem. C, 2017, 5(6): 1471-1478, Appl. Surf. Sci. , 2017, 407: 7-11 and J. Mater. Sci., (DOI: 10.1007/s10853-017-0959-z), part of the work has applied for Chinese invention patents.