當資源有限，而人口卻不斷增長的現今，開發新興可再生能源的必要性日漸加劇。銅銦鎵硒為第二世代的薄膜太陽能電池材料，相比現在市面上的矽晶太陽能電池只有百分之一的厚度，因此能夠更靈活的運用在住宅整合或是其他應用上，且其逼近矽晶太陽能電池的最高轉換效率23.35%，使得銅銦鎵硒此種材料受到產業界和學界的重視，如日本的Solar Frontier和台灣的上銀光電。
然而，銅銦鎵硒薄膜太陽能電池屬於一種異質接面太陽能電池，因此界面處的載子復合一直是阻礙效率提升的一大原因。其限制了元件的開路電壓和填充因子，為此表面鈍化是近年來人們所努力的方向，也是本論文所著眼的方向。我們使用三種方式嘗試去鈍化吸收層的表面，藉此提高元件效率。
第一部分，我們使用濺鍍的方式在吸收層表面鍍上一層3奈米的硫化銦，並經由退火後，使表面形成一銅缺的表面。經過實驗發現，此種方式確實能夠提高效率，且使表面的價帶往下彎曲。
銜接前面的實驗，由於硫化銦中的硫並沒有留在吸收層表面，並且濺鍍損傷也是無可避免的缺點。因此在第二部分，我們使用蒸鍍的方式，鍍一層一奈米的銦在吸收層表面，使OVC相在表面形成。我們也藉由此種方式改善了元件效率，且其元件和材料分析的結果和第一部分實驗相似
第三部分，我們嘗試蒸鍍氟化鉀和銦在吸收層表面，並在退火爐中退火，然而氟化鉀的吸水特性，使其在蒸鍍腔體外吸收了大量水分。在退火過程中，其氧原子進入了吸收層內部和表面且取代硒原子，進而惡化元件表現。

With limited resources and a growing population, the need to develop a new renewable energy source is growing. Copper indium gallium selenide is the second generation of thin-film solar cell materials, which is only one percent of the current Silicon solar cell thickness. Therefore, it can be more flexibly applied in building. The highest conversion efficiency of twin crystal solar cells is 23.35%, which makes the material of copper indium gallium selenide attract the attention of industry and academy, such as Japan's Solar frontier and Taiwan's Eterbright Solar.

However, CIGSe device is a heterojunction solar cell, so the carrier recombination at the interface has always been a major obstacle to efficiency improvement. It limits the open circuit voltage and fill factor of the device. To overcome this issue, surface passivation is the direction that people have worked hard in recent years, and it is also the direction of this thesis. We tried to passivate the surface of the absorber layer in three different ways in order to increase the device efficiency.

In the first part, we sputter 3 nm of indium sulfide on the surface of the absorber, and after annealing, the surface was formed into a copper-deficient surface. From the experiment result, this method can actually improve the efficiency and bend the valence band of the surface downward.

Following the previous part, since sulfur in the indium sulfide did not remain on the surface of the absorber, sputtering damage was inevitable issues. Therefore, we use an evaporation deposition to coat an one-nanometer indium on the surface of the absorber to form the OVC phase on the surface, and we also improve the efficiency of the element in this way.
In the third part, we try to evaporate potassium fluoride and indium on the surface of the absorption layer and anneal in the annealing furnace. However, the highly hygroscopic characteristics of potassium fluoride make it absorb a large amount of water outside the evaporation chamber. During the annealing process, oxygen atoms enter the interior and surface of the absorber layer and replace the selenium atom, thereby deteriorating device efficiency. 

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