The purpose of this paper was to investigate the photoluminescence(PL)properties of the composites of porous silicon(PS)/porous alumina(PA)and poly(N-vinycarbazole)(PVK).The spin coating method was used to assemble porous silicon(PS)/porous alumina(PA)with polymer(PVK).The photoluminescence properties of the composites of PS/PA

and PVK were studied.The PL spectra of the composites not only showed the peak that belongs to PS/PA but also showed the peak that belongs to PVK.At the same time

in the PL spectrum of PS/PVK

a new peak was found locating at λ=485 nm.The origin of this peak was discussed.It is possible that this peak origins from the carriers transferring from porous silicon to PVK.PVK could be viewed as a special surface state of porous silicon in the composite of porous silicon and PVK.Carriers might be excited in intern of the silicon crystal and transferring to the surface of PVK.Carriers combined on it and a new emission peak at 485 nm appeared.Furthermore

the location of the peak didn't vary with the quality of PVK.So PVK provided with a stable surface state.The composite of PA/PVK didn't show any new emission peak.But about 20 nm blue shift of the peak of PVK was found after composition.It has been reported that the conglomeration of conjugated polymer can result in the narrowness of energy band(

E

g

).During the formation of PVK polymer thin film

the conglomeration is inevitable.After PVK polymer is coated on porous alumina

the polymer will enter into the pores of porous alumina.Since the diameter of pores is about 60～70 nm

the surface area of the polymer increases.Furthermore

nano-pore structure of porous alumina prevents the PVK polymer from conglomeration.Thus

the conglomeration of PVK in pores of PVK is less than conventional PVK polymer film.The

E

g

value of the PVK on porous alumina will become bigger so that about 20 nm blue shift of PL peak of the composite is observed.Therefore

it is concluded that the nano-meter effect of porous alumina brings on the blue shift of PL spectrum for PVK.The results in this paper verified the difference of luminescence mechanism between porous silicon and porous alumina.The carriers of porous silicon are excited in the intern of silicon crystal and combined on the surface of the surface.So the carriers of porous silicon could transfer to PVK and a new PL peak appeared.However

porous alumina owns fixed luminescence center.Its carriers couldn't transfer to other places.And it is impossible for the composite of porous alumina and PVK to show a new PL peak that doesn't belong to not only porous silicon but PVK.