Silicon is king in the semiconductor technology that underpins smartphones, computers, electric vehicles and more, but its crown may be slipping, according to a team led by researchers at Penn State. In a world first, they used two-dimensional (2D) materials, which are only an atom thick and retain their properties at that scale, unlike silicon, to develop a computer capable of simple operations.
The development, published today (June 11) in Nature, represents a major leap toward the realization of thinner, faster and more energy-efficient electronics, the researchers said. They created a complementary metal-oxide semiconductor (CMOS) computer - technology at the heart of nearly every modern electronic device - without relying on silicon. Instead, they used two different 2D materials to develop both types of transistors needed to control the electric current flow in CMOS computers: molybdenum disulfide for n-type transistors and tungsten diselenide for p-type transistors.
"Silicon has driven remarkable advances in electronics for decades by enabling continuous miniaturization of field-effect transistors (FETs)," said Saptarshi Das, the Ackley Professor of Engineering and professor of engineering science and mechanics at Penn State, who led the research. FETs control current flow using an electric field, which is produced when a voltage is applied. "However, as silicon devices shrink, their performance begins to degrade. Two-dimensional materials, by contrast, maintain their exceptional electronic properties at atomic thickness, offering a promising path forward."
Das explained that CMOS technology requires both n-type and p-type semiconductors working together to achieve high performance at low power consumption - a key challenge that has stymied efforts to move beyond silicon. Although previous studies demonstrated small circuits based on 2D materials, scaling to complex, functional computers had remained elusive, Das said.
"That's the key advancement of our work," Das said. "We have demonstrated, for the first time, a CMOS computer built entirely from 2D materials, combining large area grown molybdenum disulfide and tungsten diselenide transistors."
