Terahertz and gigahertz emission from an all-silicon nanocrystal.

Abstract

Based on first-principles calculations, we predict the use of pure silicon nanocrystals as nano-oscillators in the giga- and terahertz region. Small- and large-amplitude, one-dimensional vibrations are observed. The former are spontaneously excited thermally at frequencies around 3 THz. Large-amplitude vibrations originate from oscillations between the inversion geometries of the nanocrystal and can be caused either classically by an external excitation or by quantum tunneling. The latter causes a ground-state splitting of 4.2 GHz, suggesting the use of the proposed nanocrystals as laser elements in a configuration analogous to that of the ammonia maser.