More energy efficient electronic devices thanks to new 2D semiconductors

According to researchers at the Singapore University of Technology and Design (SUTD), a recently discovered family of two-dimensional (2D) semiconductors could pave the way for high-performance, energy-efficient electronics. Their results, published in 2D Materials and Applications, could lead to the fabrication of semiconductor devices applicable in traditional electronics and optoelectronics and even potentially replace silicon-based device technology altogether.

In pursuit of miniaturization of electronic devices, a well-known trend is Moore's Law, which describes how the number of components in computer integrated circuits doubles every two years. This trend is possible thanks to the ever smaller size of transistors, some of which are so small that millions of them can be crammed onto a chip the size of a fingernail. But while this trend is still ongoing, engineers are starting to grapple with the inherent material limitations of silicon-based device technology.

Due to the quantum tunneling effect, restricting a transistor too much to based on silicon will inevitably lead to highly uncontrollable device behavior sooner or later, ”said SUTD assistant professor Ang Yee Sin, who led the study. "People are now looking for new materials beyond the silicon era, and 2D semiconductors are a promising candidate."

2D semiconductors are materials that are only a few atoms thick. Due to their nano-scale size, such materials are strong candidates as silicon substitutes in research for the development of compact electronic devices. However, many 2D semiconductors currently available are plagued by high electrical resistance when they come into contact with metals.

This sparked the team's interest in Ohmic contacts, or metal-semiconductor contacts without Schottky barriers. In their study, Ang and collaborators from Nanjing University, National University of Singapore and Zhejiang University showed that a recently discovered 2D semiconductor family, namely MoSi2N4 and WSi2N4, forms Ohmic contacts with metals. titanium, scandium and nickel, which are widely used in the semiconductor device industry.

Ang hopes the work will encourage other researchers to probe more members of the newly discovered 2D semiconductor family to discover interesting properties, too. with applications beyond electronics. "Some of them may be very poor in terms of electronic applications, but very good for spintronics, photocatalysts or as a building block for solar cells," she concluded. “Our next challenge is to systematically scan all these 2D materials and classify them according to their potential applications”.