Thin SiOx layers embedded in single crystalline silicon

Abstract In this work, we examine the structural and electronic properties of very thin suboxide layers embedded in silicon. These layers of about 2 nm width are fabricated by exposing a silicon (0 0 1) surface to molecular oxygen up to background pressures of 2×10 −6 mbar inside the growth chamber of a molecular beam epitaxy system. This layer was then overgrown with silicon. At substrate temperatures between 550°C and 600°C in situ RHEED measurements reveal single crystalline overgrowth with the 2×1 surface reconstruction reappearing after about 60 nm . Transmission electron microscopy reveals a continuous layer about 2 nm wide with some inhomogenities. Electrical transport measurements across such a barrier exhibit current blocking behavior at low temperatures up to about 0.5 V . Current at a given voltage increases with a thermal activation energy of about 50 meV . Electron transport across such barrier layers generates hot electrons which are demonstrated to excite erbium ions, leading to light emission at 1.54 μm wavelength.