The properties of multilayer structure or superlattices consisting of alternating layers of amorphous semiconductors have aroused considerable interest during the last few years. By plasma deposition and by alternating the plasma-gas mixture

we prepared multilayer films consisting of sequential layer of hydrogenated amorphous silicon (a-Si:H) and insulating amorphous silicon nitride (a-SiN

x

:H).The photolumenescence measurements have been carried out for the structure above. The experiments show that the energy (

E

p

) of the photolumenescence peak increases by 0.10eV and broadens 0.20eV as a-Si:H layer thickness is decreased from 105Å to 15Å. This is tentatively attributed to quantum size effects and two-demensional confinement in the thin a-Si:H layer. We also find striking the temperature dependence of the photoluminescence spectra. In bulk a-Si:H

the large temperature coefficient of

E

p

is usually due to thermolization down tail states based on short range disorder. We observed for all our multilayers films a photoluminescence fatigue of 10% after an exposure at 77K to 5×10

21

/cm

2

·s photons of hv=2.40eV for 30min. The photoluminescence measurements indicate that the photoluminescence spectra of anade sample is different from that of cathode sample. These results have been interpred in terms of the bonded hydrogen content in the a-Si:H layers.