Abstract In this paper, we study structures contained thin hydrogenated amorphous silicon (a-Si:H) films deposited on porous silicon multilayers (Distributed Bragg Reflector DBR) formed by electrochemical etching of crystalline silicon (c-Si) wafers. The a-Si:H thin films were deposited by the Direct-current magnetron sputtering technique in a mixture of argon and hydrogen atmosphere. It is shown in our previous work that the Bragg mirrors formed on crystalline silicon play an important role in the light trapping in a-Si:H. The structural features of porous silicon, in terms of porosity, thickness and surface roughness, were determined using spectroscopic ellipsometry. The elaborated structures were analysed by impedance spectroscopy. The fit of data obtained from the impedance spectroscopy allowed us to determine the electrical equivalent circuit. This permits the identification of the electronic behaviour of the structures and allows us to explain the role of their different components, including the interfaces. For this purpose, we have proceeded successively. First, by the characterisation of porous silicon monolayers, afterward structures formed by porous silicon multilayers as DBR and structures of a-Si:H/c-Si and a-Si:H/PSi(DBR)/c-Si are characterised. A negative capacitance was found for the heterojunction with DBR, which was attributed to the existence of defect states at the interfaces between porous and amorphous silicon.

中文翻译：

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具有多孔硅多层膜的 a-Si:H/c-Si 异质结的交流阻抗谱研究

摘要 在本文中，我们研究了沉积在通过电化学蚀刻晶体硅 (c-Si) 晶片形成的多孔硅多层膜（分布式布拉格反射器 DBR）上的包含氢化非晶硅 (a-Si:H) 薄膜的结构。在氩气和氢气的混合气氛中，通过直流磁控溅射技术沉积 a-Si:H 薄膜。我们之前的工作表明，在晶体硅上形成的布拉格镜在 a-Si:H 中的光捕获中起着重要作用。多孔硅在孔隙率、厚度和表面粗糙度方面的结构特征是使用光谱椭偏仪确定的。通过阻抗谱分析精心制作的结构。从阻抗谱获得的数据拟合使我们能够确定电气等效电路。这允许识别结构的电子行为，并允许我们解释其不同组件的作用，包括接口。为此，我们相继开展了工作。首先，通过多孔硅单层的表征，随后由多孔硅多层形成的结构如DBR和a-Si:H/c-Si和a-Si:H/PSi(DBR)/c-Si的结构被表征。发现具有 DBR 的异质结具有负电容，这是由于多孔硅和非晶硅之间的界面处存在缺陷态。通过对多孔硅单层的表征，表征了由多孔硅多层形成的后续结构如 DBR 和 a-Si:H/c-Si 和 a-Si:H/PSi(DBR)/c-Si 的结构。发现具有 DBR 的异质结具有负电容，这是由于多孔硅和非晶硅之间的界面处存在缺陷态。通过对多孔硅单层的表征，表征了由多孔硅多层形成的后续结构如 DBR 和 a-Si:H/c-Si 和 a-Si:H/PSi(DBR)/c-Si 的结构。发现具有 DBR 的异质结具有负电容，这是由于多孔硅和非晶硅之间的界面处存在缺陷态。