Light-emitting Si films formed by neutral cluster deposition in a thin O2 gas

We have fabricated the light-emitting Si-rich and oxygen-rich amorphous SiO2 (a-SiO2) films using the neutral cluster deposition (NCD) method without and with oxygen gas admitted, respectively, and demonstrate for the first time that these films show a photoluminescent feature. The Si thin films were observed by atomic force microscopy and high-resolution transmission electron microscopy, and analyzed by means of X-ray photoelectron spectroscopy, photoluminescence (PL) and FTIR-attenuated total reflection measurements. All of the PL spectra show mountainous distribution with a peak around 620 nm. It is found that the increase in the oxygen termination in the a-SiO2 films evidently makes the PL intensity increase. It is demonstrated that NCD technique is one of the hopeful methods to fabricate light-emitting Si thin films.