Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

Preface: The study of material properties is an important part of contemporary materials science. The so-called material properties refer to the quantitative measurement and description of the functional properties and utility of materials, that is, the material’s response to electrical, magnetic, optical, thermal, and mechanical loads. The source meter SMU plays a pivotal role in contemporary material science research. Choosing an SMU suitable for electrical performance testing of a certain type of material, how to reduce the test error, and what should be paid attention to in the test, these issues need to be focused on.

Preface: The study of material properties is an important part of contemporary materials science. The so-called material properties refer to the quantitative measurement and description of the functional properties and utility of materials, that is, the material’s response to electrical, magnetic, optical, thermal, and mechanical loads. The source meter SMU plays a pivotal role in contemporary material science research. Choosing an SMU suitable for electrical performance testing of a certain type of material, how to reduce the test error, and what should be paid attention to in the test, these issues need to be focused on. Tektronix Keithley’s brand enjoys a high reputation among engineers and scientists in many disciplines around the world. Its high-precision source meters (SMU), multimeters, precision power supplies, small signal testing and data acquisition products are contemporary with Tektronix’ original product lines. Materials science research provides a variety of test programs.

Nanomaterials electrical test program will be described in this article, including “Nanowire/Carbon Nanotube Test Program”, “Two-dimensional/Graphene Material Test Program”. A schematic diagram of the application scenarios, test features and selection principles of the nanomaterial electrical test SMU, combined with the type of nanomaterial or nanoelectronic device to be tested and the test points, select the most suitable SMU. 4200 C SCS is suitable for testing almost all kinds of nanomaterials. Of course, some special source meters are more suitable for some special applications.

Nanowire/carbon nanotube and Electronic device testing

Nano Wire is a one-dimensional material that is restricted below 100 nanometers in the horizontal direction (there is no restriction in the vertical direction). According to the different composition materials, nanowires can be divided into metal nanowires, semiconductor nanowires and insulator nanowires. As a type of nanomaterials, nanowires have all the characteristics of nanomaterials outlined above. Nanowires play a very important role in electronics, optoelectronics, and nanoelectromechanical devices. It can also be used as additives in composites, wires in quantum devices, field emitters and biomolecular nanosensors, etc.

The IV test is the most basic electrical performance test for nanowires/carbon nanotubes. SMU is the basic test instrument. Different types of carbon nanotubes require different SMUs for testing. The basis for SMU selection is:

•The number of SMU channels required for the sample to be tested
• Does the sample under test have pulse test requirements?
• Does the sample under test have capacitance test requirements?
•The resistance range of the tested sample, the current range applied or tested, and the voltage range applied or tested

Comprehensive testing program for nanowires/carbon nanotubes and their electronic devices

• 4200A-SCS host
• 4200 SMU module, the number of modules is determined by the number of channels
• 4200 PA, optional, according to the minimum test current, the number matches the SMU module
• 4225 PMU, an option, is determined according to the pulse demand, the number of modules is determined by the number of channels, and whether to add an amplifier is determined by the minimum test current
• 4210 CVU, optional, configured when there is a requirement for capacitance characteristic testing
•Nano probe station (third party)
• Software: Clarius

Solution advantages:

•Wide testing range, meeting the testing needs of all kinds of nanowires/carbon nanotubes and their electronic devices
• A variety of configurations to meet different application requirements
•Built-in a variety of nanowire/carbon nanotube device libraries, and automatically generate the test process of the corresponding device after calling

Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

2D/graphene material and electronic device testing

The so-called two-dimensional material (Two dimensional material) refers to a material in which electrons can only move freely (plane motion) in two dimensions of non-nanoscale (1-100nm). It belongs to the category of nanomaterials, including superconductivity, Metallic, semi-metallic, topological insulator, semiconductor, and insulator materials. The most typical representative of two-dimensional materials is graphene. Graphene is a two-dimensional structure composed of carbon atoms. Due to its excellent properties in electrical/thermal/optical aspects, it has been widely studied and used in this field. In terms of semiconductor characteristics, graphene has excellent electrical conductivity and easy doping modification characteristics, so it is used to make various semiconductor devices, such as zero band gap, top-gate graphene field effect transistors, and double-layer graphene transistors. , Bipolar superconducting graphene transistor, graphene nanoribbon field effect tube, etc. In applications, it can be used as wearable devices, sensors, charging devices, etc.

For two-dimensional/graphene materials, the four-probe method or Van der Pauw method is usually used to test the resistivity, and the Hall effect is used to test the carrier mobility and carrier concentration.

Two-dimensional/graphene materials and electrical performance testing challenges of electronic devices

• 2D/graphene materials belong to the category of nanomaterials, and the test challenges discussed above are applicable to 2D/graphene materials.

• Resistivity and Hall effect tests are both the process of adding current and voltage measurement. The device needs to be able to output current and test voltage. This means that both a current source and a voltmeter are required, and the accuracy of the current source and voltmeter must be high to ensure the test accuracy.

• Resistivity and electron mobility usually have a large range, requiring equipment with a large range of current and voltage.

• Need to cooperate with the probe station, the test equipment needs to be easily connected, and easy-to-use software is required

• When testing the Hall effect, it is usually necessary to prepare a Hall Bar (Hall Bar)

Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

Cost-effective test plan 1:

・6221 high precision pulse current source
・2182 Nanovoltmeter
・7168 Switch Card
・Probe station (third party)
・Software: self-developed

Solution advantage

・High cost performance
・With pulse current
・Delta mode
・Wide range of resistance of the tested sample (uΩ ~ TΩ)
・Nanovolt switch card does not affect the test accuracy

Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

High-performance test plan 2:

・4200A-SCS + 4200 SMU X 3 or 4
・4200 PA X 3 or 4
・Test bench (third party)
・Software: Clarius

Solution advantages:

・SMU module integrates voltage source/voltmeter/current source/ammeter into one, with high integration and easy to use
・SMU is equipped with Kelvin interface, which can effectively eliminate the influence of cable resistance when testing small resistance
・Current output accuracy is 40fA; current test accuracy is 10fA; voltage test accuracy is 80µV;
・With pulse working mode, the self-heating effect can be eliminated by using pulse test (4225 PMU hardware needs to be added)
・Clarius software can call the built-in Project, which is not only suitable for four-probe, van der Pauw, Hall effect testing for 2D/graphene materials, but also for IV CV characteristic testing of 2D/graphene electronic devices (CV characteristic testing) 4210 CVU hardware needs to be added at time)
・Open device bottom-level instructions, with compiled software, support self-programming

Nano power generation test program

Nano generators are based on regular zinc oxide nanowires, which convert mechanical energy into electrical energy in the nanometer range, making it the smallest generator in the world. At present, nano-generators can be divided into three categories: piezoelectric nano-generators, friction nano-generators, and pyroelectric nano-generators.

Test challenges faced by nano power generation

1. The current generated by the generator is small
2. The internal resistance of the generator is large, and the open circuit voltage cannot be measured accurately
3. The signal changes quickly, it is difficult to collect the voltage or current peak value

Tektronix Nano Power Generation Test Solution

High internal resistance electrometer 6517 + data acquisition instrument DMM6500 + nano power generation acquisition software is used to collect data of tiny nano power generation current. Since some of the nano generators have turned to practical application research, one of them is the direction of pressure sensing, and the testing of matrix pressure sensors is a headache for many teachers and students. In order to solve this type of problem, according to the requirements A test plan is built as follows:

Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

Contemporary Electrical Testing of Materials: Nano Testing (Part 2)

Solution advantages:

・Recommended test plan in the research field of nano power generation
・Excellent ability to carefully test
・Customized software, faster, simpler and more professional
・Upgradable to meet future testing needs of research

The Links:   G649DX5R010T G320ZAN011

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