VISIBLE LUMINESCENCE FROM NANOCRYSTALLINE SILICON FILMS PRODUCED BY PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION

Thin nanocrystalline silicon (nc-Si) films deposited by plasma enhance d chemical vapor deposition (PECVD) exhibited room-temperature photolu minescence in the visible range of the electromagnetic spectrum, High resolution transmission electron microscopy revealed that the films ar e made of Si crystals with dimensions 2-15 nm. The photoluminescence s pectra of the nc-Si films were similar to the spectra observed from po rous silicon produced by anodization and electrochemical dissolution o f crystalline Si. This similarity suggests that the luminescence mecha nism of nc-Si films is similar to the mechanism of light emission from porous silicon. The ability to manufacture luminescent Si films by me thods which are compatible with the current Si based technology, such as PECVD, can provide new possibilities in the realization of optoelec tronic devices. (C) 1996 American Institute of Physics.