Jan 29, 2021 (Nanowerk News) Two-dimensional (2D) semiconductors have emerged during the past decade as extremely promising for future electronic and optoelectronic devices. However, to unlock the significant potential of these fragile materials, we must first find a way to protect them in functional devices, while maintaining their key electronic and optical properties. A FLEET-led Australian-German collaboration addresses this issue of fragility by providing a high-performance, ultrathin, protective glass coating. They report their findings in Advanced Materials (“Ultrathin Ga2O3 Glass: A Large-Scale Passivation and Protection Material for Monolayer WS2“). Tungsten-disulfide / gallium-oxide heterostructure. (Image courtesy of the researchers) (click on image to enlarge) The incorporation of 2D semiconductors in multi-layer, solid-state structures on large scales would allow their integration into functional devices, with exciting potential use in compact, ultra-low energy electronics.

Wrapping 2D materials in protective, ultrathin glass

Being only a few layers of atoms in thickness, ‘two dimensional’ materials are inherently fragile. To date, the integration of 2D semiconductors into functional devices has been limited by this fragility, or by the scalability of the protective materials being used. Thus, we need new methods of protection that are cost-efficient and scalable, while maintaining the material’s necessary electronic and optical properties. The new study introduces ultrathin gallium-oxide (Ga2O3) glass as a new, scalable capping material for monolayer tungsten-disulfide (WS2), a key 2D semiconductor. With FLEET researchers at ANU, Monash University and RMIT, the new paper describes a novel mechanism for extraordinary protection against deposition of dielectric materials. The target material in the new study, tungsten-disulfide, belongs to the group of transition metal dichalcogenide crystals (TMDCs) and is a very promising candidate for various optoelectronic applications functional at room temperature.

Why 2D?

In 2D materials, which might be only one or a few layers of atoms in thickness, the movement of charge-carrying particles (such as electrons) are confined to only two dimensions, and some fascinating quantum effects become predominant. For example, some particles moving in two dimensions lose their ability to ‘scatter’, so that electrical resistance vanishes.

Source: https://www.nanowerk.com/nanotechnology-news2/newsid=57166.php