Ruiz-Ortega Roberto Carlos, Esquivel-Mendez Lucero Alejandra, Gonzalez-Trujillo Miguel Angel, Hernandez-Vasquez Cesar, Matsumoto Yasuhiro, Albor-Aguilera Maria de Lourdes
Departamento de Física, Instituto Politécnico Nacional-ESFM, U.P.A.L.M., San Pedro Zacatenco, CDMX 07738, México.
Instituto Politécnico Nacional-ESCOM, Ciencias Básicas, U.P.A.L.M., San Pedro Zacatenco, CDMX 07738, México.
ACS Omega. 2023 Aug 23;8(35):31725-31737. doi: 10.1021/acsomega.3c02158. eCollection 2023 Sep 5.
The cadmium sulfide (CdS) n-type semiconductor is one of the most used as a window layer in thin-film solar cells, such as CdTe, CIS, CIGS, and CZTS. Optoelectronic properties are the most important characteristics for window materials. CdS thin films obtained using the chemical bath deposition technique (CBD) have been reported; however, large amounts of precursor solutions are used, which generate considerable amounts of toxic waste. The aim of this work is to reduce the amount of precursor solutions used for CdS growth; for this, it is necessary to consider an efficient position for the substrate inside the reactor container and at the same time allow obtaining CdS thin films with adequate physical properties to be applied in the photovoltaic solar cell development. CdS thin films were deposited on soda-lime/SnO:F substrates (FTO) using the CBD technique; the substrates were placed in three different arrangements [rack system, step system (up), and step system (down)]. CdS samples with areas of 4 cm and a thickness of 27-48 nm were obtained; the X-ray diffraction patterns show CdS thin films with different polycrystalline structures. The morphological measurements reveal different surface formations depending on the substrate position, and resistivity values of around 10 Ω*cm were measured. UV-vis spectra show transmittance values of around 45-94% in the visible region with band gap energy values of around 2.1-2.36 eV. The best physical properties of CdS thin films and an efficient CBD process were obtained when the FTO substrates were located near the bottom of the reactor container with the FTO side down, leading to an optimal configuration that allows reducing the amount of precursor solutions and in this way reduces the toxic waste generated. These results are important in the photovoltaic technology process and environmental impact.
硫化镉（CdS）n型半导体是薄膜太阳能电池（如CdTe、CIS、CIGS和CZTS）中最常用作窗口层的材料之一。光电性能是窗口材料最重要的特性。已有报道使用化学浴沉积技术（CBD）制备CdS薄膜；然而，该方法使用大量前驱体溶液，会产生大量有毒废物。本工作的目的是减少用于CdS生长的前驱体溶液用量；为此，有必要考虑反应器容器内基板的有效放置位置，同时要获得具有适用于光伏太阳能电池开发的物理性能的CdS薄膜。采用CBD技术在钠钙/SnO:F基板（FTO）上沉积CdS薄膜；基板以三种不同排列方式放置[架子系统、阶梯系统（向上）和阶梯系统（向下）]。获得了面积为4平方厘米、厚度为27 - 48纳米的CdS样品；X射线衍射图谱显示CdS薄膜具有不同的多晶结构。形态测量结果表明，根据基板位置不同表面形成情况各异，测量得到的电阻率值约为10Ω·cm。紫外可见光谱显示，在可见光区域的透过率值约为45% - 94%，带隙能量值约为2.1 - 2.36 eV。当FTO基板以FTO面朝下位于反应器容器底部附近时，获得了CdS薄膜的最佳物理性能和高效的CBD工艺，这导致了一种优化配置，既能减少前驱体溶液用量，又能减少由此产生的有毒废物。这些结果在光伏技术工艺和环境影响方面具有重要意义。
