Stable hexagonal-wurtzite silicon phase by laser ablation

A stable phase of relatively large hexagonal-wurtzite silicon crystals (up to 20 μm) was directly deposited at low pressure using ultraviolet laser ablation. The films were grown on a variety of substrates at room temperature from a single crystal, cubic silicon target. Crystallites of the hexagonal-wurtzite phase of silicon were clearly identified using selected area electron diffraction. Further support for this identification was provided by confocal scanning micro-Raman spectroscopy. The deposition of hexagonal silicon films may lead to novel two-dimensional optoelectronic devices, and pave the way to studies of the electronic properties of this lower symmetry, uncommon silicon phase.