New form of Silicon could enable next-gen devices

Silicon plays an outsized role in human life. It is the second most abundant element in the Earth's crust. When mixed with other elements, it is essential for many construction and infrastructure projects.

Silicon can take different crystalline forms, called allotropes, in the same way that soft graphite and super-hard diamond are both forms of Carbon. The form of Silicon most commonly used in electronic devices, including computers and solar panels, has the same structure as diamond. Despite its ubiquity, this form of Silicon is not actually fully optimized for next-generation applications, including high-performance transistors and some photovoltaic devices.

A team developed a new method for synthesizing a novel crystalline form of Silicon with a hexagonal structure that could potentially be used to create next-generation electronic and energy devices with enhanced properties that exceed those of the "normal" cubic form of Silicon used today.

The team used Si₂₄, previously developed, as the starting point in a multi-stage synthesis pathway that resulted in highly oriented crystals in a form called ⁴H-Silicon, named for its four repeating layers in a

hexagonal structure.

The discovery of bulk ⁴H-Silicon crystals opens the door to exciting future research prospects for tuning the optical and electronic properties through strain engineering and elemental substitution and could potentially use this method to create seed crystals to grow large volumes of the ⁴H structure with properties that potentially exceed those of diamond Silicon.