In the semiconductor industry, silicon has long dominated the manufacturing of smartphones, computers, and electric vehicles. However, a research team from Penn State University has achieved a groundbreaking feat by leveraging two-dimensional (2D) materials—atomically thin yet capable of maintaining excellent electronic properties—to develop the world’s first 2D computer capable of performing simple computations. Published in Nature, this milestone marks a significant leap toward thinner, more efficient electronic devices.
The Invention of 2D Computer
Traditional complementary metal-oxide-semiconductor (CMOS) technology relies on silicon, but the team instead used two 2D materials—molybdenum disulfide (MoS₂, for n-type transistors) and tungsten diselenide (WSe₂, for p-type transistors)—to construct a fully functional CMOS computer. Unlike silicon, which suffers performance degradation at ultra-small scales, these 2D materials maintain superior properties even at atomic thicknesses.
Using metal-organic chemical vapor deposition (MOCVD), the team fabricated over 1,000 transistors and precisely tuned the manufacturing process to optimize their threshold voltage. The resulting computer operates at low voltage with minimal power consumption, achieving a maximum clock frequency of 25 kHz. While its performance still lags behind conventional silicon chips, the study proves the feasibility of 2D materials in computing. Computational models comparing the 2D computer with advanced silicon technology suggest significant room for optimization.
Though 2D material research began relatively late, around 2010, progress has been rapid. Compared to silicon’s 80-year development, this breakthrough hints at a future where electronics could become thinner, more efficient, and fundamentally transformative.
Understanding the Key Materials
What is Molybdenum Disulfide (MoS₂)?
Molybdenum Disulfide, the primary component of molybdenite, is a lustrous solid with the chemical formula MoS₂. It serves as a high-performance solid lubricant, especially under extreme temperatures and pressures, and exhibits diamagnetic properties. As a semiconductor, it can display either p-type or n-type conductivity, functioning as a photoconductor, rectifier, or energy converter. It also acts as a catalyst for hydrocarbon dehydrogenation.
Moreover, MoS₂ is emerging as a promising material for transistors. Unlike graphene (another 2D material with no bandgap), MoS₂ has a 1.8 eV bandgap, making it highly suitable for nanoelectronics. Single-layer MoS₂ transistors achieve an electron mobility of up to 500 cm²/(V·s) and an on/off current ratio of 1×10⁸.
What is Tungsten Diselenide (WSe₂)?
Like MoS₂ and tungsten disulfide (WS₂), Tungsten Diselenide is a layered material with a low friction coefficient. Its hexagonal structure resembles MoS₂: each tungsten atom bonds with six selenium atoms in a trigonal prismatic coordination, while each selenium atom forms a pyramidal linkage with three tungsten atoms. The W-Se bond length is 2.526 Å, and the interlayer Se-Se distance is 3.34 Å, held together by van der Waals forces.
With a 1.35 eV bandgap, excellent optical properties, and robust physicochemical stability, WSe₂ is ideal for applications such as photovoltaics and ultra-thin LEDs.
View more optical materials at Stanford Advanced Materials.
