| Summary: | 碩士 === 崑山科技大學 === 光電工程研究所 === 98 === CuInSe2 thin film solar cell belongs to I-III-VI tribe compound semiconductor, its contruction is chalcopyrite. And it is direct bandgap and its absorption coefficient reaches 104~105 cm-1. Its photo absorption range covers from ultraviolet to infrared, thus it is very suitable to be used as the absortion layer of thin film solar cell. Its cost is quite low and owns relative high photovoltaic transfer rate. Therefore the CIS thin film solar cell owns high develop potential.
In this study, the double-target magnetron sputtering method is used to generate Cu-In thin film. The prefabricated Cu-In precursor layers are divided into Cu/In and In/Cu structures. And they appear as two kinds of bi-layer and two kinds of multilayer-layer. Then those four kinds of Cu-In precursor layer are put into a special design quartz furnace chamber to become alloy film in high temperature and low pressure surroundings. The different combinations of temperature and time interval are applied to generated the alloy film. The better Cu11In9 phase is used to fnd the optimal combination of temperature and time interval. Then the selenization of the alloy film is completed under 500℃ to become CuInSe2 film. Finally, the binary-component phase diagram is used to adjust the various mole ratio In/(Cu+In) precursor layer by means of emaximation analysis results. From this, the secondary phase is minimumized and better selenization can be reached.
This experimental sputtering power of Cu-In precursor layer adopts the range of 200~400W. The work pressure is fixed at 2.5 mtorr. It is found by means of film thickness analysis with α-step device that the more uniform and delicate Cu-In precursor layer is obtained by sputtering power of 300W. It is shown by means of crystal analysis for precursor layer that the better Cu11In9 crystal phase can be obtained with the combination of 200℃ and 30 minutes. It is found after the selenization that mole ratio In/(Cu+In)=0.7 of Cu-In binary-component can reduce the secondary phase of CuInSe2 effectively and make the CuInSe2 phase trending to single phase. Through the comparison those various selenization analyses of CuInSe2 obtained by four kinds of Cu-In precursor layer, it concludes that the multilayer-layer of Cu/In can obtain bigger crystal and more delicate P-type CuInSe2 thin film.
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