Spray pyrolysis of chalcopyrite thin films

黄铜矿CuInS_2薄膜是一种重要的太阳能电池吸收材料。采用含cu - in和s -化合物的溶液对CuInS_2薄膜进行了喷雾热解研究。这个过程被称为薄膜的低成本过程。本研究建立了超声速喷雾热解系统，对CuInS_2薄膜的组成和表面形貌进行了研究。首先，我们尝试使用含有Cu、In和s源的混合溶液。然而，上述溶液容易形成白色沉淀，不适合喷涂沉积。因此，我们尝试了以下三个过程。1)采用Cu-In源喷涂沉积，形成Cu-In金属膜。然后用h2s气体对其进行硫化，得到CuInS_2薄膜。2)Cu-In金属膜由单质Cu和In蒸发而成。然后，喷射含有CH_3CSNH_2的溶液对CuInS_2薄膜进行硫化。3)分别用Cu-In金属膜和CH_3CSNH_2溶液进行两次喷涂沉积，形成CuInS_2薄膜。我们可以用1-3个工艺制得CuInS_2薄膜。然而，生长的CuInS_2薄膜是由纤维状化合物组成的，这与真空蒸发和H_2S硫化法制得的薄膜有很大的不同。此外，喷涂膜的x射线衍射光谱显示，KCN处理未去除氧化铜和硫化铜。因此，我们必须去除这些铜化合物，将这种薄膜应用于太阳能电池。

Chalcopyrite CuInS_2 thin film is one of the most important material as absorbers of solar cells. We studied spray pyrolysis of the CuInS_2 thin films which used solutions containing Cu-In-and S-compounds. This process is known as a low-cost process of thin films. In this research we made a supersonic spray pyrolysis system and studied CuInS_2 thin films in their composition and surface morphology.First, we tried to use a mixed solution containing Cu-,In-,and S-sources. The above solution, however, tend to form white precipitates, which is not suitable for a spray deposition. We thus tried the following three processes.1)We deposited by spraying Cu-and In-sources to form Cu-In metallic film. Afterward, we sulfurized it by H_2S gas to from CuInS_2 thin films.2)Cu-In metallic film was evaporated from elemental Cu and In. Later, a solution containing CH_3CSNH_2 was sprayed to sulfurize a CuInS_2 thin film.3)Two spray depositions of Cu-In metallic film and a CH_3CSNH_2 solution were successively made to form a CuInS_2 thin film.We could make CuInS_2 thin films by 1-3) processes. The grown CuInS_2 films, however, consist of fiber-like compounds, which are quite different from those gown by a vacuum evaporation and H_2S sulfurization. Moreover, x-ray diffraction spectra from sprayed film show the existence of Cu oxide as well as Cu sulfide, which are not removed by KCN treatment. We, thus, have to remove those Cu compounds to apply this film for solar cells.