太陽電池材料銅銦硒薄膜晶體結構之研究

Crystal Structure of Solar Cell Material CuInSe2 thin films

鄭鈞元(Chun-Yuan Cheng)

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2006年)

摘要

在本研究中，即提供一系列的多晶系單層銅銦硒(CulnSe2)薄膜，其Cu/In原子比值為1.7 和0.5，透過利用物理汽相沈積系統，在銅(Cu)和銦(In)的濺鍍和硒(Se)蒸汽中求得。在微觀結構方面的變化(表面形態、晶粒尺寸和缺陷上) 銅銦硒薄膜在改變化學計量比從含銅量多(Cu-rich)的到含銅量少(Cu-poor)的研究利用掃描式電子顯微鏡鏡(SEM) 和穿透式電子顯微鏡鏡(TEM)來分析觀查。通常，含銅量多的薄膜用相對低的缺陷密度顯示大的顆粒，同時含銅量少薄膜顯示非常平坦的缺陷、雙晶和疊差的缺點，與小顆粒。多晶結構的雙層銅銦硒薄膜由沉積且成長一個含銅量少的階層在一個含銅量多的階層上面。雙層含銅量少的薄膜顯示了較大晶粒(>3毫米)。高解析度穿透式電子顯微晶格影像顯示出一稀薄的連貫層(約為20奈米)位於晶界的雙方在一輕微含銅量少的薄膜。穿透式電子顯微鏡能量分佈X-射線光譜學(EDX)分析表明晶粒邊界區域適合有比內部晶粒含銅量少更為輕微地含銅量少的薄膜。連貫薄層和含銅量少在輕微地含銅量少的薄膜的晶界能與型態反轉有關。表面形態和多晶結構銅銦硒的晶界能提供暸解銅銦硒的發展行為和銅銦硒元件的成果。

並列摘要

In this study, a series of polycrystalline single-layer CulnSe2 thin films with Cu/In atomic ratios between 1.7 and 0.5 were grown by using a physical vapor deposition system Cu and In sputtering and Se evaporation. The variation in the microstructure (surface morphology, grain size and defects) of the CulnSe2 thin films on gradually changing the stoichiometry from Cu-rich to Cu-poor was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In general, Cu-rich thin films showed large grains with relatively low defect densities, while Cu-poor thin films exhibited highly planar defects, twins and stacking faults, with small grains. Polycrystalline bi-layer CulnSe2 thin films were also grown by depositing a Cu-poor layer on the top of a Cu-rich layer. The bi-layer Cu-poor thin films exhibited large grains (>3 ?m). High-resolution TEM lattice image shows a thin coherent layer (~20nm) at the both sides of the grain boundary for a slightly Cu-poor film. TEM energy dispersive x-ray spectroscopy (EDX) analyses indicate that the grain boundary region is more Cu-poor than the intra-grain for the slightly Cu-poor film. The coherent thin layer and more Cu-poor at the grain boundary of the slightly Cu-poor film could be related to a type inverse. The surface morphologies and the grain boundaries of the polycrystalline CuInSe2 could provide an understanding of the growth behavior of CuInSe2 and the performance of CuInSe2 devices.

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