Scientists have overcome a limitation in graphene, allowing them to utilize the material as a functional semiconductor at terahertz frequencies, exhibiting 10 times the mobility of silicon.
Researchers have successfully developed the world’s inaugural graphene-based semiconductor, potentially opening avenues for significantly faster PCs and future quantum computers. This novel semiconducting substance, derived from epitaxial graphene—a specific crystal structure of carbon bonded to silicon carbide—facilitates greater electron mobility than silicon. Transistors manufactured using this material can operate at terahertz frequencies, a speed tenfold greater than silicon-based transistors found in contemporary chips, as outlined in a study published on January 3 in the journal Nature.
Semiconductors exhibit characteristics of both conductors and insulators, allowing electron movement through the material under specific temperature ranges and energy applications.
While silicon has been the go-to semiconductor material for almost every chip, it is approaching its limitations, according to lead researcher Walt de Heer, a professor at the Georgia Institute of Technology. These constraints include the maximum speed at which transistors can switch between on-off positions, heat generation through resistance, and the smallest achievable size.
Graphene, composed of a single layer of carbon atoms arranged in a hexagonal lattice, proves to be a superior conductor compared to silicon, resulting in less resistance for electron movement.
The main hurdle preventing the incorporation of graphene into electronics has been the absence of a “band gap”—a minimum energy requirement for electron movement when an electric field is applied. Band gaps are essential for transistor functioning.
To address this issue, researchers fused graphene onto silicon carbide using specialized furnaces and a distinct heating and cooling process. Through a process known as “doping,” where atoms donating electrons are added to the graphene, a functional graphene semiconductor with a band gap was created. Notably, this graphene-based semiconductor not only functions effectively but can also seamlessly integrate into existing manufacturing processes.
The study suggests potential applications of graphene-based semiconductors in quantum computing due to the quantum mechanical wave-like properties exhibited by electrons in graphene, especially at extremely low temperatures. While further research is needed to explore this potential, the researchers acknowledge the uncertainty of whether graphene-based semiconductors can outperform current superconducting technology in advanced quantum computers.
