Novel Semiconductor Born from Graphene and Glass

A study published in Advanced Materials reports that an international team led by materials scientists at Rice University has successfully synthesized a two-dimensional hybrid material, glaphene, by chemically combining graphene and silica glass into a single, stable compound.

Some of the most promising materials for future technologies are composed of atomically thin layers. Graphene, for example, is a single layer of carbon atoms arranged in a hexagonal lattice and is known for its exceptional strength and electrical conductivity.

Although hundreds of 2D materials have been identified, combining them into entirely new materials remains a challenge. Most efforts involve stacking these layers like cards, but the layers often interact only weakly with one another.

The layers do not just rest on each other; electrons move and form new interactions and vibration states, giving rise to properties neither material has on its own.

Sathvik Iyengar, Study First Author and Doctoral Student,  Rice University

More significantly, Iyengar noted that the new technique could be applied to a wide range of 2D materials, enabling the design of hybrid materials for use in quantum devices, photonics, and next-generation electronics.

Iyengar added, “It opens the door to combining entirely new classes of 2D materials, such as metals with insulators or magnets with semiconductors to create custom-built materials from the ground up.”

The team developed a two-step, single-reaction method to grow glaphene from a liquid precursor containing both silicon and carbon. By carefully adjusting oxygen levels during heating, they first formed graphene and then shifted conditions to promote the formation of a silica layer.

To achieve this, the researchers built a custom high-temperature, low-pressure setup over several months in collaboration with Anchal Srivastava, a visiting professor from Banaras Hindu University in India.

Iyengar stated, “That setup was what made the synthesis possible. The resulting material is a true hybrid with new electronic and structural properties.”

After synthesizing the material, the team worked with Manoj Tripathi and Alan Dalton at the University of Sussex to verify its structure. An unexpected result in the data provided the first hint that glaphene was something new.

Using Raman spectroscopy—a technique that detects vibrational signatures of atoms by analyzing shifts in laser light—the researchers observed signals that did not match those of graphene or silica. These unusual vibrational properties suggested that the layers were interacting more strongly than expected.

In typical 2D stacks, layers are held together by weak van der Waals forces, similar to magnets sticking to a refrigerator. In contrast, glaphene’s layers exhibit stronger interactions, enabling electrons to move between them and producing novel behaviors.

To investigate further, Iyengar consulted Brazilian spectroscopy expert Marcos Pimenta. The observed anomaly turned out to be an artifact, serving as an important reminder that even reproducible results must be interpreted with caution.

To better understand the behavior of the bonded layers at the atomic level, the researchers collaborated with Vincent Meunier at Pennsylvania State University. By comparing experimental results with quantum simulations, they found that the graphene and silica layers form partial bonds at the interface, allowing electrons to be shared across layers.

This hybrid bonding changes both structure and function, effectively transforming a metallic and insulating material into a new type of semiconductor.

“This was not something only one lab could do. This research was a cross-continental effort to create and understand a material nature does not make on its own,” Iyengar stated.

Iyengar recently spent a year in Japan as a fellow of the Japan Society for the Promotion of Science (JSPS) and was the inaugural recipient of the Quad Fellowship—a program created by the governments of the United States, India, Australia, and Japan to support early-career scientists working at the intersection of science, policy, and diplomacy.

Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Engineering and professor of materials science and nanoengineering, emphasized the broader significance of the work. While the discovery of glaphene is important in itself, he said the real excitement lies in the potential to chemically combine fundamentally different 2D materials.

A guiding principle that Iyengar attributes to his advisor is reflected in the team’s approach.

“Since I started my Ph.D., my adviser has encouraged me to explore mixing ideas that others hesitate to mix. Professor Ajayan has also said that true innovation happens at the junctions of hesitation, and this project is proof of that,” he said, quoting Ajayan, who is a Corresponding Author on the study alongside Meunier.

The research received funding from multiple sources: the Sussex Strategy Development Fund; the National Science Foundation Graduate Research Fellowship Program (2236422); the Air Force Office of Scientific Research-funded Rice–Penn State collaborative project (FA9550-23-1-0447); the Quad Fellowship; the Instituto de Ciência e Tecnologia de Nanomateriais de Carbono; the Fundação de Amparo à Pesquisa do Estado de Minas Gerais; and the Brazilian National Council for Scientific and Technological Development.

Iyengar, Srivastava, Meunier, and Ajayan have expressed interest in pursuing intellectual property rights for their method, and a provisional patent application has been filed in the United States.

Rice researchers lay groundwork for designer hybrid 2D materialsPlay