What Is Van Der Waals?

van der Waals Equation Calculator

Number of Moles (n): Volume (V, in L): Temperature (T, in K): Van der Waals constant a (L²·atm/mol²): Van der Waals constant b (L/mol): Calculate Pressure (P)

Smooth Silicon Wafer Surface for van der Waals Adhesion

A PhD researcher working in a medical device technology group requested a quote for the following.

I'm looking for silicon wafers with the smoothest surface available for use in van der Waals adhesion experiments. The diameter doesn't really matter too much, as long as it's 1" or greater 500 micron thick.

Reference #126399 for specs and pricing.

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van der Waals Growth On Superconducting Wafers

A professor requested a quote for the following.

I have been wondering if you also offer Aluminum Wafers (Al)?  If you do, do you have any experience on how to passivate the Al surface for transferring the Wafers from cleanroom to the MBE > chamber? I am planning to perform van der waals growth on superconducting Wafers.

Reference #205161 for specs and pricing.

Application is 2D van-der-Waals Material Exfoliation and 2D Transfer of These Materials

A university tenured professor requested a quote for the following.

I have two students who are planning to exfoliation MoSe2 onto silicon wafers. I heard that I could use such a wafer or similar. Would you agree? Do you have something on stock? Silicon (Si) wafer with SiO2 thin layer Grade: prime CZ Conductive type: P-type/Boron-doped Orientation: (100) ± 0,5° Diameter: 4 inch Thickness: 0,5 mm Surface: one side polished / one side etched TTV: ≤ 10 μm Flats: SEMI standard Resistivity: 0,001-0,005 Ω·cm Particle: < 10 @ 0,3 μm SiO2: dry chlorinated thermal oxide & FGA SiO2 thickness: 285 nm ± 5% SiO2 surface needs to be hydrophobic.

Reference #283595 for specs and pricing.

Dry Thermal Oxide for van der Walls Experiments

A Ph.D. student in materials science and engineering requested a quote for the following.

We need Dry Thermal SiO2 film thickness: 90nm Diam: 100mm silicon wafer Grade : Prime Doping: P or N type Resistivity: 0.1-0.5 (ohm-cm) Wafer thick: 500 um or less Polish: SSP

We are using these wafers for research on 2D materials (graphene, hBN and other van der Waals materials).

Reference #256985 for specs and pricing.

Why Ultra-Flat Substrate Surfaces Are Essential for van der Waals Experiments

In the rapidly evolving world of 2D materials research, such as graphene, MoS₂, and other transition metal dichalcogenides (TMDs), the surface quality of your substrate is not just important—it’s critical. Van der Waals (vdW) experiments, which involve the stacking and interfacing of atomically thin layers, depend heavily on the flatness and cleanliness of the underlying substrate.

🧭 What Are van der Waals Materials?

Van der Waals materials are held together by weak, non-covalent interactions between their layers. These interactions are highly sensitive to surface uniformity. Any substrate irregularity—such as pits, particles, or warping—can distort layer alignment, introduce mechanical strain, or inhibit proper adhesion.

💡 Why Ultra-Flat Silicon Wafers?

Ultra-flat silicon wafers (such as those offered by UniversityWafer, Inc.) provide:

• Sub-nanometer surface roughness (RMS)

• Minimal total thickness variation (TTV)

• High planarity across large areas

These characteristics make them ideal platforms for mechanical exfoliation, dry transfer, and heterostructure stacking, where alignment at the atomic level is essential. Additionally, silicon wafers are chemically stable, easy to handle, and compatible with most lab and cleanroom environments.

🔍 Clean Surfaces = Better Interfaces

In vdW assembly, surfaces must be free of:

• Organic contamination

• Particulates

• Oxide growth (unless intentional)

A poor surface can introduce charge traps, strain fields, or wrinkling in 2D layers, leading to unreliable device performance or experimental noise.

🧪 Beyond Silicon: Other Flat Substrates

Depending on the experiment, researchers also use:

• Fused quartz – optically transparent and flat

• Sapphire – chemically stable and hard

• Hexagonal boron nitride (h-BN) – atomically flat and inert

Each substrate serves a purpose, but all must meet the same requirement: ultra-flat, low-defect surfaces.

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In short, the success of your van der Waals experiments hinges on the quality of your substrate. Ultra-flat wafers are not a luxury—they’re a necessity. Whether you're fabricating next-gen FETs or exploring quantum phenomena, start with a solid foundation.

 

What is van der Waals and how does it relate to semiconductors?

Van der Waals (vdW) forces are weak intermolecular forces that arise due to temporary dipoles formed when electrons fluctuate around atoms or molecules. While relatively weak compared to chemical (covalent or ionic) bonds, vdW forces play a major role in materials science — including semiconductors — especially at the nanoscale.

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🧲 Types of van der Waals Forces

1. Dispersion (London) forces – caused by momentary shifts in electron density.

2. Dipole–dipole interactions – between permanent dipoles.

3. Dipole–induced dipole interactions – between a dipole and a neutral molecule.

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⚙️ van der Waals in Semiconductors

1. 2D Materials and van der Waals Heterostructures

• Materials like graphene, MoS₂, WS₂, and h-BN are 2D semiconductors or insulators with layers held together by vdW forces.

• These can be stacked without the need for lattice matching, forming van der Waals heterostructures.

• This allows researchers to design new semiconductor devices with tailored electronic, optical, and mechanical properties.

2. No Dangling Bonds

• vdW materials have surfaces free of dangling bonds, making them ideal for low-defect interfaces.

• This improves device performance by reducing surface states and charge traps.

3. Tunneling and Weak Coupling

• vdW gaps (the space between layers) can act as tunnel barriers, enabling devices like tunneling transistors or vdW FETs (Field Effect Transistors).

4. Flexible and Transparent Electronics

• vdW materials enable flexible, ultra-thin, and transparent semiconducting layers — useful in wearable tech, photodetectors, and next-gen displays.

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🧪 Examples of van der Waals Semiconductors

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💡 In Summary:

Van der Waals forces enable the stacking of different 2D materials to form new kinds of semiconductor devices that don't rely on traditional epitaxial growth. This opens the door to novel device architectures, heterostructures, and flexible electronics that aren't possible with bulk semiconductors like silicon.

Researching Macro Properties of the van der Waals/Casimir Forces

My team and I are researching macro properties of the Van Der Waals/Casimir forces and would like to purchase the flats that are more likely to exhibit the known behavior of sticking to each other. Being more mechanical than materials engineers, we wanted to know which of your 1" flats would be most likely to do this? Also, what would be the cost for one Aside from that and the minimization of warping, no. I'd like 2 for now to do preliminary tests. 

Reference #275500 for specs and pricing.