The successful development of the first terahertz scanning tunneling microscope system has continuously contributed to scientific research in my country

[ Hot Focus on Chemical Machinery and Equipment Network ] If Feynman's "nano" concept has made a conceptual design for the construction of a microscopic world, then the invention of the scanning tunneling microscope (STM) is a crucial step in realizing this microscopic world.
one step
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STM is a scanning probe microscopy tool for observing and locating single atoms.
Its basic principle is based on quantum mechanical tunneling and three-dimensional scanning.
Through the atomic-scale tip, at a height of less than one nanometer, different samples are Perform ultra-high-precision scanning imaging
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STM is mainly used to describe the three-dimensional atomic structure of the surface, and to study the properties of substances at the nanoscale.
Using scanning tunneling microscopes, the nano-processing of the surface can also be realized, such as directly manipulating atoms or molecules, and completing the etching, modification and processing of the surface.
Write directly,
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Recently, the Aerospace Information Research Institute of the Chinese Academy of Sciences (Guangzhou Park)-Guangdong Greater Bay Area Aerospace Information Research Institute (hereinafter referred to as the "Greater Bay Area Research Institute") successfully developed a terahertz scanning tunneling microscope system, which is superior to the atomic level.
(Angstrom-level) spatial resolution and better than 500 femtosecond temporal resolution, becoming the first domestically developed THz scanning tunneling microscope system
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　　THz-STM system
 

　　STM uses an extremely thin needle with a single atom at the tip to approach the sample surface.
When the needle tip and the sample surface are very close, that is, less than 1 nanometer, the electron cloud of the atoms at the tip of the needle and the atoms on the sample surface will occur.
overlap
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At this time, if a bias voltage is applied between the needle tip and the sample, the electrons will pass through the potential barrier between the needle tip and the sample to form a tunneling current of nanoamp level 10A
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By controlling the constant distance between the needle tip and the surface of the sample, and making the needle tip move along the surface accurately three-dimensionally, the surface information such as surface topography and surface electronic state can be recorded
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　　Using these multi-probe devices, samples can be characterized in multiple modes, including tunneling mode imaging of electron energy state density, acting as electrodes in contact mode, and detecting field-effect transconductance as floating electrodes
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In 2013, Frank Hegmann, a professor at the University of Alberta in Canada, combined terahertz pulses and STM for the first time to achieve sub-picosecond time resolution and nanometer spatial resolution.
Subsequently, German, American and other scientific research teams have carried out related technical research
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　　It took nearly 12 months for the terahertz research team of the Greater Bay Area Research Institute to break through the core key technologies such as terahertz and scanning tunnel tip coupling, terahertz pulse phase modulation, and successfully developed the first domestic terahertz scanning tunneling microscope (THz-STM).
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The microscope has Angstrom-level spatial resolution and sub-picosecond temporal resolution (improved by more than 1 million times), and can achieve precise detection (femtosecond-Angstrom level) with high temporal and spatial resolution at the same time.
The ultrafast kinetic processes of electrons provide a powerful technological means and are crucial for the development of novel silicon nanoelectronics and atomic-scale devices operating at terahertz frequencies
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THz-STM can be used in new quantum materials, micro-nano optoelectronics, biomedicine, ultrafast chemistry and other fields, and is expected to achieve original scientific research results with important international influence
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　　Original title: The first terahertz scanning tunneling microscope system was successfully developed to continuously help my country's scientific research