PHOTOLUMINESCENCE CHARACTERISTICS OF OXIDIZED HYDROGENATED NANOCRYSTALLINE SILICON FILM

We have observed visible photo-luminescence (PL)from an oxidized hydro genated nanocrystalline silicon (nc-Si:H)film which was prepared in a plasma enhanced chemical vapor deposition (PECVD) system and post-trea ted by thermal oxidization processes. At low oxidization temperature ( T-ox) below 500 degrees C, silicon oxyhydrides and silicon oxides are formed at the surface of grains; while at high T-ox above 500 degrees C, the surface of grains is covered by alpha-SiO2. PL around 650 nm-75 0 nm is observed as Tox ranges from 100 degrees C to 700 degrees C dur ing which the grain size (d(c)) varies from 2.7 nm to 5.1 nm. At T-ox > 700 degrees C, the Id,is larger than 5.1 nm and PL peak shifts to 92 0 nm. The quantum size effect and surface states model was employed to explain our experimental results. (C) 1998 Acta Metallurgica Inc.