Scanning-tunnelling microscope for vibrating example and measurement method thereof

A technology of scanning tunneling and measurement methods, applied in scanning probe microscopy, measurement devices, scanning probe technology, etc., can solve the problems of not being able to identify what kind of atoms or molecules are being observed, and low resolution.

Inactive Publication Date: 2009-02-11
SUN YAT SEN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Existing scanning tunneling microscopes cannot identify what kind of atoms or molecules are being observed
[0004] STM detects the tunneling current between atoms and has atomic-scale resolution; while AFM detects the interaction force between the atoms at the tip of the probe and the surface of the object within a certain range, and its resolution is usually lower than that of STM.

Method used

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  • Scanning-tunnelling microscope for vibrating example and measurement method thereof
  • Scanning-tunnelling microscope for vibrating example and measurement method thereof
  • Scanning-tunnelling microscope for vibrating example and measurement method thereof

Examples

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Embodiment 1

[0034] Example 1: Realize atomic discrimination

[0035] attached image 3 The STM topography diagram, the amplitude diagram and the phase diagram of the alternating tunneling current signal measured simultaneously by the invention are given. The measurement conditions are: tunnel current 0.8nA, sample bias voltage 0.1V; AC excitation signal peak-to-peak value 1.0V, AC excitation signal frequency 5kHz.

[0036] Within this scanning range, micro-regions composed of platinum and gold are likely to exist on the surface of the sample at the same time. From the topography, many crystal grains can be seen, but the region composed of these two elements cannot be distinguished. But on the current amplitude diagram and the phase diagram, there are two distinct regions, and the region with smaller current amplitude corresponds to the region with smaller phase. The mechanical properties of platinum and gold are similar, and the intensity of the effective excitation signal in the micro-r...

Embodiment 2

[0037] Embodiment 2: Resolving multi-phase alloy materials:

[0038] attached Figure 4 The STM surface topography diagram, the amplitude diagram and the phase diagram of the alternating tunnel current signal measured by the present invention are given. Before the test, after grinding and polishing, a layer of platinum atoms was sputtered on the surface to enhance its surface conductivity. The measurement conditions are: tunnel current 0.8nA, sample bias voltage 0.1V; AC excitation signal peak-to-peak value 2.0V, AC excitation signal frequency 15kHz.

[0039] Sn-Pb alloy is a typical two-phase coexistence alloy material. From the topography, there are many grains, but the regions of these two different phases cannot be distinguished. But on the current amplitude map and phase map, there are two distinct areas, the area with smaller current amplitude corresponds to the area with smaller phase; in the dark area in the lower left corner, there is also a small bright area . I...

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Abstract

The invention provides a scanning tunneling microscope for a vibrating specimen and a measurement method thereof. The scanning tunneling microscope comprises a scanning head (1), a preamplifier (2) and a scanning tunneling microscope controller (4), wherein the scanning head (1) is provided with a probe (1-1), the preamplifier (2) is provided with a current / voltage converter (2-1), a low pass voltage amplifier (2-2) and a band pass voltage amplifier (2-3), a phase detector (3) is also arranged, and respectively connected with the band pass voltage amplifier (2-3) and the scanning tunneling microscope controller (4), and the phase detector (3) is also provided with a voltage signal generating device (3-1) which is connected with a piezoelectric vibration exciter (1-3) arranged under the probe (1-1). The invention provides a device for measuring the characteristics of nanometer or atom scale while measuring the tunneling current by applying light mechanical vibration to the detected specimen on the basis of STM, and a measurement method for realizing the recognition of the categories of atom or molecule or obtaining the physical properties of the material such as the micro-elasticity.

Description

technical field [0001] The invention belongs to the technical field of scanning probe microscopes, and in particular relates to a scanning tunneling microscope capable of realizing the identification of atomic or molecular species of a sample to be measured, and a measurement method using the microscope. technical background [0002] Scanning probe microscope (SPM) mainly includes two types: scanning tunneling microscope (STM) based on tunneling effect and atomic force microscope (AFM) based on interatomic force. [0003] In STM the sample is usually immobilized. When the distance between the metal probe and the tested conductive sample is adjusted below the nanometer scale, the applied DC bias causes tunnel current to occur between the probe and the tested sample. Through the feedback circuit, keep the distance between the probe and the measured conductive sample constant (constant height mode) when scanning, usually get a two-dimensional image of the density of states on ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N13/12G01Q60/14
Inventor 丁喜冬张进修曾荣耀
Owner SUN YAT SEN UNIV
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