Summary: | 碩士 === 國立彰化師範大學 === 機電工程學系 === 103 === This study investigated the influence of different components produced of the absorbing layer on second phases, as it relates to the performance and leakage current of Cu(In,Ga)Se2 (CIGS) thin film solar cells. The CIG metal precursor layer was prepared by sputtering with a ternary alloy target, and then added a Cu or In thin film of 75-150 nm, the selenium sulfide process were used to form a CIGSSe absorbing layer. The experimental result found that the CIGSSe grains increases with the increase of amount of Cu element. On other hand, increase of amount of Cu element will increase the Cu2-xSe second phase, and result in more leakage current of device. Additional, increase of amount of Cu element will increase the energy gap of the film surface due to the diffusion of Ga element from back to surface of the absorbent layer. The Voc of device but decreased may be due to the affect of leakage current caused far more than Ga enhance Voc. Excessive Cu or In the presence of the film surface Cu2-xSe, InSe phases result in P-N interface strength deteriorates easily by applying a negative bias in the short wavelength range. The device with excessive In element have a worse the intensity of P-N junction than device with excessive Cu element, more likely to cause breakdown. In this study, the optimal efficiency of 13.06% was obtained in reference cell.
Keywords: CIGSSe thin film solar cell; Cu2-X Se phase; InSe phase; leakage current
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