Abstract

Recent observations of efficient, visible room-temperature photoluminescence (PL) in porous Si has stimulated an intense debate regarding its physical origin. Various investigators have attributed this PL to quantum-size effects, to surface chemistry, or to a combination. The random heterogeneous structure of porous Si complicates experimental analysis. Here, we report on Raman and PL measurements of (110) Si grating structures with linewidths in the 5–50-nm range. We have developed a simple, inexpensive, scalable interferometric and dry-oxidation technique for fabrication of large area arrays of mesoscopic-scale Si structures.^1,2 Figure 1 shows a scanning- electron-microscope (SEM) picture of a typical Si structure used for these measurements. This picture shows a cross section of 2-p.m-high Si walls (0.34-p.m pitch) with a linewidth of 30 run. These structures are parallel to the {112} direction, the walls face the [ID] directions, and the top of the grating walls are in a {110} direction.

© 1994 Optical Society of America