Cadmium telluride (CdTe) thin films were synthesized by using a two-electrode electrodeposition method on a conductive glass fluorine-doped tin oxide (FTO) substrate. The structural analysis revealed that the deposited CdTe thin films have mixed-phase cubic zinc blends and hexagonal structures in as-prepared and annealed forms with pH depositions of 1.8, 2.5, and 3.5. When the deposition pH is 3.0, only a single-phase cubic structure is observed. The crystallite sizes were 6, 14, 17, and 14 nm for as-prepared and 12, 20, 23, and 19 nm heat-treated samples for corresponding pH values of 1.8, 2.5, 3.0, and 3.5, respectively. The energy bandgaps were recorded in the range 1.38–1.58 eV for as-deposited samples and 1.35–1.5eV for annealed samples for pH values of 1.8–3.5, respectively. The surface image showed that CdTe thin films uniformly covered the glass substrate while the surface morphology of CdTe changed with pH. The availability of both Cd and Te was verified by compositional analysis. The average surface roughness recorded 50.08, 52.08, and 24.00 nm for as-prepared samples and 56.46, 78.73, and 47.17 nm for heat-treated samples for the pH values of 2.5, 3.0, and 3.5, respectively. The overall result shows that the pH value of 3.0 produced a CdTe film of good quality for solar cell application.

中文翻译：

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电解液pH值对太阳能用电沉积CdTe薄膜性能的影响

采用双电极电沉积法在导电玻璃掺氟氧化锡（FTO）基板上合成了碲化镉（CdTe）薄膜。结构分析表明，沉积的 CdTe 薄膜在制备和退火状态下具有混合相立方锌混合物和六方结构，沉积 pH 值为 1.8、2.5 和 3.5。当沉积pH为3.0时，仅观察到单相立方结构。所制备的样品的微晶尺寸为 6、14、17 和 14 nm，热处理样品的微晶尺寸为 12、20、23 和 19 nm，相应的 pH 值分别为 1.8、2.5、3.0 和 3.5。 pH 值为 1.8-3.5 时，沉积样品的能带隙范围为 1.38-1.58 eV，退火样品的能带隙范围为 1.35-1.5eV。表面图像显示CdTe薄膜均匀地覆盖在玻璃基板上，而CdTe的表面形貌随pH值的变化而变化。通过成分分析验证了 Cd 和 Te 的有效性。 pH 值为 2.5、3.0 和 3.5 时，制备样品的平均表面粗糙度分别为 50.08、52.08 和 24.00 nm，热处理样品的平均表面粗糙度分别为 56.46、78.73 和 47.17 nm。总体结果表明，pH 值3.0 可以生产出质量良好的CdTe 薄膜，适合太阳能电池应用。