Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnická 10, 162 00 Prague, Czech Republic.
PV-Center, Centre Suisse d'Électronique et de Microtechnique, Rue Jaquet-Droz 1, CH-2002 Neuchâtel, Switzerland.
Sci Rep. 2016 Dec 6;6:37859. doi: 10.1038/srep37859.
Thin, light-absorbing films attenuate the Raman signal of underlying substrates. In this article, we exploit this phenomenon to develop a contactless thickness profiling method for thin films deposited on rough substrates. We demonstrate this technique by probing profiles of thin amorphous silicon stripes deposited on rough crystalline silicon surfaces, which is a structure exploited in high-efficiency silicon heterojunction solar cells. Our spatially-resolved Raman measurements enable the thickness mapping of amorphous silicon over the whole active area of test solar cells with very high precision; the thickness detection limit is well below 1 nm and the spatial resolution is down to 500 nm, limited only by the optical resolution. We also discuss the wider applicability of this technique for the characterization of thin layers prepared on Raman/photoluminescence-active substrates, as well as its use for single-layer counting in multilayer 2D materials such as graphene, MoS and WS.
薄的、吸光薄膜会使底层基质的拉曼信号衰减。在本文中，我们利用这一现象开发了一种用于探测粗糙基底上沉积的薄膜的无接触式厚度剖面方法。我们通过探测沉积在粗糙晶体硅表面上的非晶硅条纹的轮廓来证明这一技术，这是一种在高效硅异质结太阳能电池中应用的结构。我们的空间分辨拉曼测量能够非常精确地绘制整个测试太阳能电池活性区域中非晶硅的厚度图；厚度检测下限远低于 1nm，空间分辨率可达 500nm，仅受光学分辨率限制。我们还讨论了该技术在拉曼/光致发光活性衬底上制备的薄膜的特性化中的更广泛适用性，以及它在单层计数中的应用，例如在多层二维材料如石墨烯、MoS 和 WS 中。
