Bandgap engineering of a-SiC:H thin films was carried out to assess the material light absorption without compromising its photoelectrochemical water splitting capabilities. The tailoring was performed by varying the hydrogen concentration in the semiconductor and by post-deposition isochronical annealing treatments from 100 C to 700 C. Bandgap values were obtained by fitting the fundamental absorption region of the absorption coefficient using three different models. Differences among bandgap values extracted by these methods and its correlation with the a-SiC:H structure, demonstrate that structural features, rather than a hydrogen rearrangement or depletion, would be responsible for annealing induced optical bandgap increment. These features are taking in advantage for the bandgap engineering of a-SiC:H without changing Si-C stoichiometry. Optical bandgap values for p-doped a-SiC:H samples gradually increased from 2.59 to 2.76 eV upon performing each annealing step until 600 C. Temperature at which an enhancement in the electric performance is observed. We believe, these results will help on the design of monolithic tandem solar cells for water splitting applications.

进行了a-SiC：H薄膜的带隙工程，以评估材料的光吸收，而不会损害其光电化学水分解能力。通过改变半导体中的氢浓度并通过从100 C到700 C的沉积后等时退火处理进行定制。通过使用三种不同的模型拟合吸收系数的基本吸收区域来获得带隙值。这些方法提取的带隙值之间的差异及其与a-SiC：H结构的相关性表明，结构特征（而不是氢重排或耗尽）将导致退火引起的光学带隙增加。这些功能在不更改Si-C化学计量的情况下，可用于a-SiC：H的带隙工程。在执行每个退火步骤直至600℃时，p掺杂a-SiC：H样品的光学带隙值从2.59 eV逐渐增加到2.76 eV。在观察到电性能增强的温度下。我们相信，这些结果将有助于设计用于水分解应用的单片串联太阳能电池。