| Metamaterial is a new kind of artificial material, which can realize different electromagnetic properties through designing various sub-wavelength structural units. The magnetic resonance characteristics of metamaterial can be controlled by the design of the subwavelength structure unit and the size of the material, which can achieve the magnetic field effect in a range of wavelengths. Previous scholars have some research on the application of metamaterial to thin film solar cell, but the high absorption of light by absorbed layer is mainly concentrated in the microwave band or infrared band rather than the visible light band. In addition, the metal component of the metamaterial solar cell they are designed is not continuous, therefore can not be used to the electrode of the solar cells. In this paper, we design two tupes grating metamaterial solar cells, and then systematically calculate and study the reason of the visible light absorption enhancement of CdTe thin film by metamaterial.CdS and CdTe films were prepared by magnetron sputtering at low and high sputtering power, and characterize the prepared films with XRD, SEM and ellipsometry. Based on the experimental and theoretical analysis, the effects of sputtering power and sputtering pressure on the crystallization behavior and morphology of CdS and CdTe films were analyzed, and the effect of corrosion on the properties of CdTe thin films was discussed.Ag films were prepared by electron beam evaporation, and the properties of the prepared Ag films was characterized with SEM and ellipsometry.Based on the theory of electromagnetic resonance of the metamaterial, the structure of CdTe thin film solar cell with single grating and double grating metamaterial are designed, then calculate the absorption efficiency of visible light in the rang of 500 nm and 900 nm by absorbing layer CdTe thin film of metamaterial CdTe thin film solar cell and traditional structure CdTe thin film solar cell by commercial finite element software COMSOL. The influence of the grating width, the grating thickness and the CdTe thickness on the absorption enhancement on the rang of 500~900 nm of the visible light band by absorbing layer CdTe thin film based the single grating CdTe film solar cell is calculated and analyzed. Then the absorption efficiency on the same visible light band of CdTe thin film is calculated over the different thickness, the different grating period and the different CdTe thickness in double grating metamaterial CdTe thin film solar cells. |
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