The optimizations of the emitter region and the metal grid of a concentrator silicon solar cell are il- lustrated. The optimizations are done under 1 sun, 100 suns and 200 suns using the 2D numerical simulation tool TCAD software. The optimum finger spacing and its range decrease with the increase in sheet resistance and con- centration ratio. The processes of the diffusion and oxidization in the manufacture flow of the silicon solar cells were simulated to get a series of typical emitter dopant profiles to optimize. The efficiency of the solar cell under 100 suns and 200 suns increased with the decrease in diffusion temperature and the increase in oxidation tempera- ture and time when the diffusion temperature is lower than or equal to 865 ℃. The effect of sheet resistance of the emitter on series resistance and the conversion efficiency of the solar cell under concentration was discussed.
The electromagnetic interaction between Ag nanoparticles on the top of the Si substrate and the incident light has been studied by numerical simulations. It is found that the presence of dielectric layers with different thicknesses leads to the varied resonance wavelength and scattering cross section and consequently the shifted photocurrent response for all wavelengths. These different behaviours are determined by whether the dielectric layer is beyond the domain where the elcetric field of metallic plasmons takes effect, combined with the effect of geometrical optics. It is revealed that for particles of a certain size, an appropriate dielectric thickness is desirable to achieve the best absorption. For a certain thickness of spacer, an appropriate granular size is also desirable. These observations have substantial applications for the optimization of surface plasmon enhanced silicon solar cells.
