Silicon Epitaxy and Poly-Silicon layers. Silicon, an indirect gap semiconductor, can emit
light with 10% efficiency at room temperature, provided that it is in the form of low-
dimensional (quantum dots or wires) nanostructures. Ivanda's group is producing porous
silicon from three types of silicon layers: Silicon On Insulator (SOI), Silicon Epitaxy and
Poly-Silicon layers. Anodizing with DC and AC current of these layers creates new
morphology that show intense photoluminescence. The research objectives are new simple
and inexpensive techniques for preparation of porous silicon for the development of high
sensitive gas sensors, thermoelectric and biocompatible materials. The structures with
novel morphologies that exhibit strong photoluminescence were discovered. The
luminescence mechanisms and the relationship between bandgap energy, luminescence
energy, and size of nanostructures are investigating.