以熱注射法合成二硫化銅銦奈米粒子與其薄膜特性分析

Abstract

本實驗利用熱注射法將溶於十八油胺（Oleylamine）的硫粉（S-OLA）注入到含有銅銦前驅物（(Cu,In)-OLA）的溶液中製成硫化銅銦（CuInS2）奈米粒子。控制熱注射反應溫度在180□C，經60min反應後可合成出黃銅礦（Chalcopyrite）結構，大小為10 nm的CuInS2奈米粒子。XRD分析顯示降低反應溫度能抑制纖鋅礦（Wurtzite）CuInS2相的產生，控制熱注射反應溫度於180□C且增加反應時間時可提升黃銅礦CuInS2相的結晶性。本研究嘗試將合成的CuInS2奈米粒子分散在甲苯（Toluene）製成漿料，再利用浸鍍（Dip-coating）沉積CuInS2薄膜，但成膜品質不佳；添加環己酮（Cyclohexanone）能夠明顯的改善將料與基板的分子間作用力並增加薄膜與基板的附著性，可獲得高緻密度、無龜裂（Crack）的薄膜。將CuInS2薄膜在真空、Ar與Ar+10%H2混合氣體中進行後退火，實驗結果顯示在真空及Ar氣氛退火會形成In2O3相，且隨著退火溫度提高CuInS2薄膜氧化更趨明顯；於Ar+10%H2混合氣體氣氛中之退火則能抑制In2O3相的形成並改善薄膜的結晶特性，也能降低CuInS2本質缺陷使得載子濃度下降而改善了載子遷移率，但所製成之CuInS2薄膜之載子濃度仍高於應用所需，仍待後續研究改善之。

CuInS2 nanoparticles were prepared by injecting the sulfur which had been dissolved in the oleylamine (S-OLA) into the hot oleylamine solution containing copper(I) chloride (CuCl) and indium(III) chloride (InCl3). By adjusting the reactive temperature and time of hot-injection process, CuInS2 nanoparticles about 10 nm in size were successfully formed at 180□C for 1 hr. X-ray diffraction analysis revealed that the wurtzite phase is suppressed by decreasing the reactive temperature and the crystallinity of chalcopyrite phase improves with the increase of reactive time. The CuInS2 nanoparticles were consequently dispersed in toluene to form the ink for preparing the CuInS2 thin films on the glass subatrate via the dipping-coating process. It was found that the CuInS2 content of ink is crucial to the film quality. Moreover, the incorporation of cyclohexanone was found to improve the wetting property of ink on glass subatrate, which benefits the preparation of uniform and crack-free CuInS2 films. Post annealing study indicates the heat treatments in Ar or vacuum ambient result in the formation of In2O3 phase in thin-film samples and the annealing in Ar+10%H2 ambient is able to eliminate such an undesired oxide phae in CuInS2 thin films. However, further study is required since the carrier concentration of CuInS2 film was still high and impratical for solar cell device fabrication.