TEM ELECTROMECHANICAL IN-SITU TESTING METHOD OF ONE-DIMENSIONAL MATERIALS

• US 20200132574A1
• Filed: 07/16/2018
• Published: 04/30/2020
• Est. Priority Date: 04/18/2018
• Status: Active Grant

• Current Assignee: Dalian University of Technology
• Original Assignee: Dalian University of Technology
• Inventors: ZHANG, Zhenyu, CUI, Junfeng, CHEN, Leilei, WANG, Bo, GUO, Dongming
• Granted Patent: US 11,313,774 B2
• Time in Patent Office: Days
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01N 1/31 Apparatus therefor
• CPC Class Codes: G01N 1/36 Embedding or analogous mounting of samples
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 2001/305 Fixative compositions
• CPC Class Codes: G01N 2001/364 using resins, epoxy
• CPC Class Codes: G01N 2203/0019 Compressive
• CPC Class Codes: G01N 2203/0023 Bending
• CPC Class Codes: G01N 2203/0286 Miniature specimen; Testing on microregions of a specimen
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/2202 Preparing specimens therefor
• CPC Class Codes: G01N 3/08 by applying steady tensile or compressive forces G01N3/28 takes precedence
• CPC Class Codes: G01N 3/20 by applying steady bending forces G01N3/26, G01N3/28 take precedence
• CPC Class Codes: H01J 2237/2062 Mechanical constraints
• CPC Class Codes: H01J 2237/2802 Transmission microscopes
• CPC Class Codes: H01J 37/261 Details

Abstract

A TEM electromechanical in-situ testing method of one-dimensional materials is provided. A multi-function sample stage which can compress, buckle and bend samples is designed and manufactured. A carbon film on a TEM grid of Cu is eliminated, and the TEM grid of Cu is cut in half through the center of the circle. The samples are dispersed ultrasonically in alcohol and dropped on the edge of the semicircular grid of Cu with a pipette. A single sample is fixed on the edge of a substrate of the sample stage with conductive silver epoxy by using a micromechanical device under an optical microscope, and conductive silver paint is applied to the surface of the substrate of the sample stage; and an electromechanical in-situ testing is conducted in a TEM. This provides a simple and efficient sample preparation and testing method for a TEM electromechanical in-situ observing experiment.

Claims

1. A TEM electromechanical in-situ testing method of one-dimensional materials, designing and manufacturing a multi-function sample stage which can compress, buckle and bend samples, wherein the samples are fixed with conductive silver epoxy by using a micromechanical device under an optical microscope, and conductive silver paint is applied to the surface of a substrate of the multi-function sample stage;

an electromechanical in-situ testing is conducted to the samples under the TEM, and the change process of the sample microstructures is observed, wherein

(1) the samples are one-dimensional materials of nanowires and nanotubes;

(2) the multi-function sample stage is formed by processing an SOI chip through etching and laser stealth cutting methods, is made of boron doped P-type silicon, has overall sizes of 2-3 mm in length, 1.5-2 mm in width and 0.25-0.4 mm in thickness, and is made by processing through the laser stealth cutting method;

the multi-function sample stage comprises two parts;

an underlayer and a substrate, wherein the substrate has a thickness of 5-15 μ

m;

firstly, a groove with a width of 1.5-1.7 mm and a depth of 30-70 μ

m is processed from the underlayer through etching;

then, a groove with a width of 4-100 μ

m and a depth of 20-60 μ

m is etched on the substrate;

the samples are fixed on the edge of the substrate perpendicular to the direction of the groove;

a ratio of the extending length of the samples from the substrate to the sample diameter is less than 10;

a compression experiment is conducted;

the samples are fixed on the edge of the substrate perpendicular to the direction of the groove;

the ratio of the extending length of the samples from the substrate to the sample diameter is more than 10;

a buckling experiment is conducted;

the samples are fixed on the edge of the substrate parallel to the direction of the groove;

the extending length of the samples from the substrate is more than 2 μ

m; and

a bending experiment is conducted;

(3) a carbon film on a TEM grid of Cu is eliminated, and the TEM grid of Cu is cut in half with a blade through the center of the circle to form a semicircular grid of Cu;

(4) the samples are dispersed in an alcoholic solution, and ultrasonically processed for 1-3 min;

then, the samples are dropped at the edge of the semicircular grid of Cu with a pipette;

(5) if the sample diameter is more than 100 nm, a single sample is moved from the edge of the semicircular grid of Cu to the edge of substrate of the sample stage under the optical microscope by using the micromechanical device;

if the sample diameter is less than 100 nm, a single sample is moved from the edge of the semicircular grid of Cu to the edge of substrate of the sample stage by using a FIB system;

(6) the samples are fixed with conductive silver epoxy by using a micromechanical device under the optical microscope, and put in the air for 4-8 hours to solidify the conductive silver epoxy; and

then a layer of conductive silver paint is applied to the surface of the substrate of the multi-function sample stage;

(7) the sample stage to which the samples are fixed is fixed on a sample holder of a sample rod of a TEM in-situ nanomechanical system by using the conductive silver paint;

(8) the sample holder is fixed on the sample rod by screws; and

an electromechanical in-situ observing experiment is conducted on the samples under the TEM by using a flat head boron-doped diamond pressing needle or a flat head tungsten pressing needle.