Abstract
Thin film nanocrystalline porous silicon layers have been fabricated from amorphous silicon films using dc plasma hydrogenation and subsequent annealing at temperatures about
450
°
C
on silicon substrates. Plasma power densities about
5.5
W
∕
cm
2
were found to be suitable for etching of the silicon film and the creation of nanoporous layers. The nanoporous structures show visible luminescence at room temperature as confirmed by photoluminescence spectroscopy. The effects of plasma power and annealing temperature on the grain size and luminescence properties of these layers have been investigated by scanning electron microscopy, transmission electron microscopy, photoluminescence, and cathodoluminescence. It was observed that by lowering the temperature during the hydrogenation step, the diameter of the grains increased, whereas lowering the plasma power density caused the distribution of the porous surface structures to become less widely distributed and the formation of more packed structures. In addition, infrared spectroscopy has been used to investigate the origin of the light emitting behavior.