Generally，the defect states in semiconductors can play a vital role in degrading its electrical and photoelectronic performance. Some deep-level defects can be introduced artificially into the indirect band gap semiconductors and then transformed to be optical centers，which could enable the intensive light emission and therefore make them be promising materials for devices such as solar cells with high-efficiency，low-cost and light-emitting devices for those indirect band gap semiconductors of the IV group semiconductors^［1-3］ and halide perovskites ^［4-6］. Ion implantation has been demonstrated to be an effective way to bring in optical centers in silicon，which is an optically nonactivated materials but the footstone of the whole microelectronics，and are promising to promote the silicon to be the optimal candidate for realizing the great “optoelectronic and microelectronic integration” engineering.

Although the optical defects can be effectively formed in the Si film by Si⁺ ion implantation and annealing processes on the top layer of the SOI substrate，the light emitting efficiency still can’t meet the level of chip integration application^［7，8］. The integration of optical quantum amplification structures on the luminescent Si based materials，which is believed to be one of the most effective means，has attracted extensive attention in recent years to enhance the luminescence performance of the defect silicon. Periodical metal or semiconductor nanostructure array with certain dielectric constants was generally used to fabricate the photonic crystals，which can amply the light emission of solid matter.

Since the introduction of such optical defect mode requires the nano-level photolithographic process with the characteristic of sophisticated，complicated，and relatively high-cost，meanwhile the obtained photonic crystal exhibits a gain effect merely at a relatively small area within the micro-level range，the large-scale application of the silicon-based light-emitting materials photonic crystals with the defect mode is seriously limited.

Plasma enhanced luminescence on metal surfaces is also one of the current research hotspots. The radiation efficiency ^［9］ of the luminous body was effected by the density of photon states according to calculations by Gontijo ^［10］ et al. When the electromagnetic waves radiated ^［11］ by the electronic transitions match the wavelength of the plasma resonance，the probability of excitons radiative transitions will be increased by 55 times. In addition，the luminous efficiency of the luminous body is given by the following formula：

where，r_r is the radiative transition probability and r_nis the non-radiative transition probability. The luminous efficiency of the sample^［12］ is

where，Lωex term represents the local electric field intensity，and theZωem one represents the energy distribution of the metal nanoparticles for radiative and non-radiative transitions.

The dynamic state of electromagnetic waves in media with different dielectric constants can be obtained by solving the Maxwell's equations. The principle of finite-difference time-domain method（FDTD）is solving Maxwell's equations by replacing the differential with difference between space and time，and constructing the Yee cell to mesh the space. Therefore，the FDTD simulation is believed to be an effective mean to acquire the parameters of photonic crystal，which could meet the expected experiment result.

In this work，FDTD was used to theoretically strengthen gains of luminous efficiency by simulating the structure and optimizing the parameters of photonic crystal in advance. Thus，the size of PS beads can be etched to the designed size by the ICP process，and a plasma enhanced luminescence SOI material ^{［13，14］} with a photonic crystal structure can be acquired by depositing Au film on the periodically arranged spheres via the vacuum coating machine.

The PS spheres is arrayed in close-packed hexagonal pattern with the diameter of 500 nm. Generally，the ultimate penetration depth in the metal is between 10 nm and 100 nm，and the Si wafer size is set to 3.4 μm ×（ / 2）3.4 μm. The Si layer was set to 100 nm，and the number of beads was set to 6 × 6. The default dielectric constant of software is 2.56. The Perfect Metal Absorption Layer（PMAL）acts as the absorption layer and the number of absorption layers is set to 32.

Since the space is divided into grids to solve Maxwell's equations by the time domain difference method，the grid completely fills all the areas in the middle of the PML layer. Considering the simulated wavelength range is 700 nm-960 nm，the grid is set to 70 nm × 70nm. By taking the calculation speed and accuracy into account，a relatively small area is selected to place a new 1 nm × 1 nm × 1 nm grid，as the light source.

Purcell factor，in direct proportional to the enhancement factor，is used to illustrate the luminous intensity gain performance. Moreover，the Purcell factor is as follow：

where，（λ_c/n）is the wavelength of the substance， Q and V are the quality factor and mode volume，respectively. Mode volume V is mainly related to electric field distribution and dielectric constant.

Since both Au nanospheres and nano-islands structures owned gain effects for the waveband beyond 700 nm，the luminescence of Si nanocrystals was enhanced by the plasma resonance of the Au film in this work. Since the plasma was mostly distributed on the metal surface，nanophotonic crystals array of Au film was designed to enhance luminescence，with the thickness and the hole diameter of Au film being 200 nm and 480 nm，respectively.

Figure 1 shows the specific experimental process as follows. First，samples were cleaned with the Shiraki method ^［15］，and the cleaned samples were self-assembled with a layer of 500 nm diameter PS beads with the LB method. Second，etch the PS beads for 240 s with ICP. After the pellets were etched，PS beads were placed in a drying oven at 155 °C for 3 minutes，which were melted and softened to form pillars. The vacuum coating machine was utilized to vapor deposit the Au film of 200 nm thick. Finally，samples were annealed at 160 °C for 5 minutes，and the pellet was washed away in a tetrahydrofuran solution.

Figure 2（a）and（b）show a sharp contrast of the simulated electric field intensity. The electric field intensity at the position of the nanopore is large，however，it is almost zero at the area covered by the Au film，which means that it is difficult for the light source to penetrate the Au film.

Figure 2（c）shows the SEM characterization of the prepared sample，the holes and holes have been linked to each other. It is related to the preparation of the sample. Since the thickness of the Au film is 200 nm. Therefore，it is difficult to dissolve the PS beads only in the tetrahydrofuran solution completely. After annealing at 160 ℃ for 5 minutes，the PS beads will melt which will cause the holes of the Au film to be larger than the diameter of the PS spheres（220nm）in this process.

Figure 3 shows that the nanodisk photonic crystals structure has an effective enhancement on the PL intensity from the defect in SOI. In fact，the intensities of the two broadening PL peaks from the photonic crystals at the 760-820 nm and 830nm-960 nm band have been enhanced by 24 and 126 times in compared with the original PL ones，respectively. N⁺ dose of 1×10¹⁴ cm^-2 and Si ⁺ implantation dose of 5×10¹⁴ cm^-2 were implanted in samples.

As shown in Figure 3，the two PL wave packs at 760~820 nm and 830~960 nm can basically consistent with the simulation results. There is a certain shift between the simulation results and the experimental results. This may be related to the introduction of defect modes in the photon forbidden band，and the energy level of the mode will greatly enhance the luminescence at that frequency. The enhancement of wave packets at 760~820 nm and 830-960nm is caused by the direct recombination emission of exciton from small and large nanocrystalline silicon crystals under the quantum confinement effect，respectively. Purcell factor plays a role of amplifying intrinsic luminescence. Nano-silicon crystals of different sizes are superimposed and formed Broad band. In addition，plasma photonic crystals have two enhanced luminescence mechanisms，both photonic crystal resonance and surface plasma resonance. The combination of these two effects leads to a frequency shift of the luminescence peak position，which also makes the actual PL spectrum of the sample and the simulated Purcell factor have a mismatch in some areas. The Purcell effect is mainly reflected in the enhancement of the spontaneous emission rate of the charge of the Au film photonic crystal of the periodic array relative to the unstructured charge，which also supports the enhancement of the photoluminescence effect. In addition，the enhancement of the normalized intensity of the PL wave packet at 760~820 nm by the photonic crystal is about 24 times，and the enhancement of the PL wave packet at 830-960nm is about 126 times，and the overall luminous peak intensity of the Au film sample is greater than that of the uncovered sample，which means that the nanodisk Au film array can effectively enhance the photoluminescence of Si ⁺ / Ni ⁺ ions co-implanted with SOI.

Figure 4 shows the photon band gap diagram of the simulated the Au nanodisk-array photonic crystals. When the emission frequency of the material is within 3.6×10¹⁴-3.7×10¹⁴ Hz，which is the photonic forbidden band，the normalized luminous intensity given by the simulation in Figure 3 is particularly low at 810 nm-830 nm（3.6×10¹⁴-3.7×10¹⁴ Hz），which is also consistent with the luminescence of the Au film sample. Then Figure 4 shows a bottom U-shaped "photon level" appeared at the bottom of the forbidden band，which indicates that the light at 857 nm can be enhanced mostly，so there is a luminescence enhancement at 857 nm section. Compared with the simulation results，it has been substantially enhanced. This may be caused by the deformation of the dislocation strain region in the sample preparation process，which leads to the introduction of a defect “energy level” at 857 nm，which substantially enhances the spontaneity of the sample，similar to the photonic crystal with a defect mode.

A photoluminescence enhancement of SOI by Si⁺/Ni⁺ ions co-implantation process is introduced in this paper. The FDTD software was used to simulate the Au nanodisk-array photonic crystals，and the corresponding structural parameters and gain effects were obtained. In this work，film thickness and aperture of Au nanodisk-array photonic crystals holes is 200 nm and 480 nm，respectively. Subsequently，the SOI substrate with the photonic crystal structure is prepared by PS balls and the metal coating. The experimental and simulated results show that the Au nanodisk-array photonic crystals not only have a substantial enhancement effect on the light on the horizontal plane and but also resonate with the plasma on the hole wall in the direction of propagation to effectively enhance the luminescence. In addition，the normalized intensity of the photonic crystal to the PL wave packets of 760~820 nm and 830~960 nm are increased by 24 times and 126 times，respectively. It is caused by the structurally stable defect emission center and the direct recombination emission of nano-silicon crystal exciton under the quantum confinement effect，respectively. In general，this work provides a simple and easy-to-use method for the preparation of effective luminescence-enhanced films that can be effective to sample with larger areas，and it can be approximately fitted with theoretical calculations，and it is beneficial to manufacture silicon-based light-emitting devices.