Silicon was a main material of micro-electronic devices.It was possessed of better advantage than other semiconductor materials.But semiconductor silicon was not regarded as one of candidates in optoelectronic materials because of its indirect bandgap and lower light efficiency.Thus its application in the optoelectronic devices was restricted.In 1990

Canham published that porous silicon sample fabricated by electrochemical anodization etch possesses exhibits very intense photoluminescence(PL) emission.Its light efficiency is the same comparing with direct bandgap compound semiconductor GaAs.It becomes a popular study target that realizes Si-based photoelectricity integration

because Si-based emitting material may become base material of future photoelectricity integration.Some of rare-earth ions are the better light emitting ions

the rare-earth ion doping into silicon by using ion-implantation was adopted more and more.For studing light efficiency of rare earth doped Si-based films

the beneficial try was made.The photoluminescence spectra of PSsamples and PLspectra of PSsamples treated by HNO

3

were studied

the relation of photoluminescence properties and surface structure was discussed.Rare-earth ion Nd is implanted into monocrystal Si wafers at the energy of 99 keVand with a dose of(1×10

17

cm

-2

) using metal vapor vacuum arc(MEVVA) ion implantation.The rapid annealing was made at temperature of 1000 ℃ in the atmosphere of N

2

for 20 s.The above samples were treated by anodization method under the conditions: electric current density of 30 mA/cm

2

;time of 10 min and electrolysis liquid

V

(HF):

V

(C

2

H

5

OH))=1:1.Then part porous samples were treated by HNO

3

.PLspectra were measured by F-3010 fluorescence photospectrometer for the above samples at room temperature and compared these PLspectra with those of PS.The results show emission peak of PSsamples doped by Nd is similar with emission peak of monocrystal porous silicon.But the intensity of peak have obviously increase under the same condition of electrochemical anodization etch

the 563 nm emission peak appear blue-shift and its FWHMdecreases.Besides light emission efficiency of the PSsamples that were treated by HNO

3

is higher than those of ordinary PS(samples) under the same measuring conditions.Comparing with monocrystal porous silicon

it was found that porous silicon doped by Nd form average nanometer silicon post structure

its light emission efficiency had a elevation.The photoluminescence intensity of those PSsamples treated by HNO

3

had a significant improvement.