We compare the photoluminescence (PL) properties of silicon (Si) singl
e quantum well structures, consisting of an either amorphous or crysta
lline Si layer of 3 nm thickness, embedded between silicon-nitride lay
ers. These structures are grown by plasma-enhanced chemical vapor depo
sition on Si substrates. After crystallization of the originally amorp
hous Si layers and passivation by hydrogen, strongly polarized PL is o
bserved in the entire visible spectrum. In contrast, a reference struc
ture without the 3 nm silicon layer, but otherwise identical, shows PL
in the red and infrared only, but also strongly polarized. Thus, the
PL in the blue and green part of the spectrum comes from recombination
via Si quantum well states, while the red and infrared PL is due-to s
tates at the interface between crystalline Si and silicon-nitride. (C)
1996 American Institute of Physics.