Visible light emission from silicon nanostructures

The fabrication of Si-based light emitting materials is a very active area of research: We have pursued two avenues of research that have provided int eresting prospects for practical applications. 1. Bright quantum-confined l uminescence can be obtained from Si/SiO2 superlattices. Placing them in an optical microcavity results in a pronounced modulation of the photoluminesc ence (PL) intensity with emission wavelength. The superlattice PL efficienc y can be considerably enhanced and its peak wavelength and bandwidth modifi ed selectively. 2. For porous semiconductors, a method that allows the writ ing of visible light emitting patterns of arbitrary shape down to the nanom eter scale is described. The process relies on selective electrochemistry f or pore formation at surface defects created by focused ion beam implantati on of Si.