New insight into nanostructured materials like mesoporous silicon could open the door for improved semiconductors and thermoelectrics in the future. Notably, scientists have worked for years to create more resilient silicon to drive computing and other industries forward. However, their understanding of the microscopic carrier transport mechanisms found in nanostructured silicones was limited.
Thankfully, a team of innovative engineers from HZB released a detailed study1 documenting the exact behavior of one of the most highly touted nanostructured materials: mesoporous silicon. Their research could pave the way for medical, thermoelectric, computing, and sustainability breakthroughs. As such, their report is seen by many as a game changer. Here’s what you need to know.
Mesoporous Silicon (pSi)
The benefits of mesoporous silicon have been understood for many years. However, how it achieved these favorable characteristics under certain circumstances was still a mystery until recently. Mesoporous silicon features a unique structuring that can modify phonon dispersion, enabling a higher degree of thermal transport across its surface.
To accomplish this task, mesoporous silicon leverages nanometer-sized pores that enable it to support electrochemical anodization in hydrofluoric (HF) acid. This structure allows it to offer a high degree of flexibility to engineers, allowing them to adjust key parameters like distribution, porosity, pore size, connectivity, and orientation.
More Understanding is Needed
While mesoporous silicon has been studied for decades, its charge transport mechanism remained unclear until now. The latest research provides a definitive explanation, revealing that charge carriers move through extended electronic states above a disorder-dependent mobility edge rather than relying on phonon-assisted hopping. This breakthrough could unlock new applications for this high-performance material. Recognizing the need for further understanding, a team of engineers has set off to reveal the inner workings of mesoporous silicon and how exactly it operates.
Mesoporous Silicon Study
The study “Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon,” published in the journal Science, sets out to describe in great detail the intricacies of the transport properties and processes of pSi.
The researchers looked into lattice vibrations (phonons) and how their orientations and other factors altered the material characteristics. This approach provides unique insights into the microscopic carrier transport mechanism.
As part of the study, the researchers fabricated mesoporous silicon layers using electrochemical anodization in hydrofluoric (HF) acid, a well-established process that enables precise control over pore size, porosity, and connectivity. Through temperature-dependent electrical conductivity and thermopower measurements, the researchers identified how microscopic disorder affects charge transport in mesoporous silicon.
Source – HZB
The tiny pores combine with liquids to create a hydrodynamic flow that resides within nanochannels. Researchers studied key details including the disorder-dependent mobility edge between localized and extended states.
Mesoporous Silicon Test
The team then tested their findings using custom-made wafers. Uniquely, they utilized a 4-hour etching process to create p-doped silicon wafers in electrolytes containing HF acid. Specifically, the custom-built wafers were anodized in a 4:6 electrolyte solution. The solution featured a chemical makeup of 48 vol% HF and 99 vol% ethanol.
Notably, the team could adjust every aspect of the silicon, including pore sizes, porosity, and interconnectivity of the etched pore networks. The process of etching of p-type [001]-oriented silicon wafers was tested across various types of silicon.
The team noted that they required conductivity of σ=50−100S cm−1 to operate and that structure provided an etching current density of j=12mA cm−2. The results of the process were a μ160μm thick, self-supporting 5cm membrane capable of electrical and thermal conductivity.
Mesoporous Silicon Test Results
The test results shed some light on the unique reactions that take place when dealing with mesoporous silicon. Specifically, the team integrated a Seebeck Analyzer to accurately document electrical conductivity and thermopower.
As part of the test, the engineers tracked HF concentration, current density, and etching time. Additionally, the engineers used an in-line four-point probe technique to track the electrical conductivity at a maximum current of 1 mA. They discovered a nitrogen gas atmosphere creates unique oxidation patterns at higher temperatures.
Mobility Edge
The next test involved monitoring the mobility edge to see exactly how the phonons interact. The researchers used the Meyer–Neldel compensation rule to confirm that charge transport occurs in extended states above a disorder-dependent mobility edge, overturning previous models that suggested charge carriers relied on multi-phonon-assisted hopping between localized states.
The study revealed that weave-like structures exist and are crucial to the migration of electrons in the process. These structures are fundamental to the transport process and play a role in thermal conductivity as well.
Keenly, the rate of phonon transfer is governed by extended states above a disorder-dependent mobility edge. This discovery clarifies the charge transport mechanism in mesoporous silicon, showing that charge carriers move through extended states above a disorder-dependent mobility edge, rather than relying on multi-phonon-assisted hopping between localized states, as some earlier models suggested. This discovery allows engineers to document key details of the process, opening the door for more use case scenarios.
Conductivity Decreases
Since mesoporous silicon is synthesized from highly conductive boron-doped wafers, it displays some unique properties. Ironically, the material is a major conductor of electricity. For one, the team noted that conductivity decreases with increasing disorder. These materials lose conductivity when set up in certain pore structures.
Temperature-Dependent Thermopower Measurements
Another key discovery is the link between conductivity and temperature in mesoporous silicon. The scientist quickly determined that the material was thermally activated. Understanding this core component of the material enabled engineers to achieve energy values of 860meV.
Mesoporous Silicon Benefits
There are several benefits that mesoporous material brings to the market. For one, it’s a far more sustainable alternative. Mesoporous silicon is completely biocompatible. This structure means that the material won’t cause adverse reactions in living creatures, making it ideal for drug transport systems.
Mesoporous Silicon Researchers
The Mesoporous Silicon study was led by engineers from HZB. The first author of the study is Dr. Tommy Hofmann. He received additional support from Dr. Klaus Habicht, Haider Haseeb, Danny Kojda, and Natalia Gostkowska-Lekner. Now the team seeks to expand their research and seek out a strategic partnership to further their mesoporous silicon development.
Applications
There are a lot of applications that this new type of nanostructured material can be used for. Already, there’s talk of utilizing the material as a next generation thermal insulator. The material has the ideal properties and can provide low cost and reliable thermal transfer capabilities.
Quantum Computers
One particularly exciting application for mesoporous silicon is in quantum computing. Since silicon-based qubits must be operated at cryogenic temperatures (below 1 Kelvin), mesoporous silicon’s exceptionally low thermal conductivity could make it an ideal thermal insulator, preventing heat absorption and maintaining qubit stability.
New Semiconductors
Already, there’s a lot of discussion surrounding the use of this material to create better semiconductors. Mesoporous silicon provides enhanced thermal conductivity of crystalline or polycrystalline silicon, resulting in better performing machines. In the future, scientists will delve deeper into mesoporous silicon and its many benefits to unlock more use cases.
Biosensors
Mesoporous silicon material is ideal for biosensors as well. This system can help with vital medical processes like drug delivery. Already, biosensors have helped to improve liver treatments, which are normally a problem due to the organ constantly flushing out toxins. Biosensors can targe the hard to reach areas, ensuring drug delivery.
Power Generation
Mesoporous silicon could play a vital role in future power generation systems. Its nanostructured design could improve thermal management in semiconductor applications where traditional silicon’s high thermal conductivity has been a limitation. This could open new doors in photovoltaics, nanoelectronics, and thermoelectric. That would improve current systems significantly while supporting more sustainable, affordable, and green energy infrastructure.
Companies Leading the Thermoelectric & Battery Industries
Several companies have secured a spot in the battery and thermoelectric sectors, which could see a boost from the mesoporous silicon study results. These firms continue to innovate and bring more efficient technologies to market. Here’s one company that has built a reputation as a leader in next-generation battery development.
Enovix Corporation
Enovix (ENVX -9.59%) entered the market with the goal of revolutionizing lithium-ion battery technology through its proprietary 3D silicon-anode architecture. The company was founded in 2007 and is headquartered in Fremont, CA. It has positioned itself as a key innovator in high-density energy storage solutions.
Enovix Corporation (ENVX -9.59%)
Enovix remains a standout in the advanced battery sector, leveraging its cutting-edge silicon-anode technology to improve battery performance, cycle life, and energy density. Unlike traditional graphite anodes, Enovix’s approach increases energy storage capacity while maintaining structural stability. This innovation is particularly relevant as mesoporous silicon continues to gain attention for its potential role in battery anodes.
Today, Enovix is a leading player in the silicon-anode battery market, a segment expected to grow as demand for high-performance energy storage solutions rises. The company’s technology addresses key limitations in conventional lithium-ion batteries, offering faster charging times, longer lifespans, and improved efficiency. As such, Enovix remains a compelling investment option for those looking to gain exposure to the next generation of battery innovation.
Latest on Enovix
Mesoporous Silicon – The Future of Semiconductors and More
Mesoporous silicon and other nanostructured materials have a bright future in the manufacturing processes of the future. These materials offer high-performance thermal conductivity and flexibility, which makes them the ideal solution for many of today’s most important applications. As such, it’s worth congratulating the engineers of the mesoporous study for shedding light on the inner workings of this incredibly helpful material.
Learn about other cool material science breakthroughs now.
Study Reference:
1. Hofmann, T., Haseeb, H., Kojda, D., Gostkowska-Lekner, N. and Habicht, K. (2025), Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon. Small Struct. 2400437. https://doi.org/10.1002/sstr.202400437