Chen Wenjian, Taskesen Teoman, Nowak David, Mikolajczak Ulf, Sayed Mohamed H, Pareek Devendra, Ohland Jörg, Schnabel Thomas, Ahlswede Erik, Hauschild Dirk, Weinhardt Lothar, Heske Clemens, Parisi Jürgen, Gütay Levent
Laboratory for Chalcogenide-Photovoltaics (LCP), Carl von Ossietzky University of Oldenburg Carl-von-Ossietzky-Straße 9-11 26129 Oldenburg Germany
Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) Meitnerstraße 1 70563 Stuttgart Germany.
RSC Adv. 2019 Aug 28;9(46):26850-26855. doi: 10.1039/c9ra02847a. eCollection 2019 Aug 23.
Molybdenum (Mo) is the most commonly used back-contact material for copper zinc tin selenide (CZTSe)-based thin-film solar cells. For most fabrication methods, an interfacial molybdenum diselenide (MoSe) layer with an uncontrolled thickness is formed, ranging from a few tens of nm up to ≈1 μm. In order to improve the control of the back-contact interface in CZTSe solar cells, the formation of a MoSe layer with a homogeneous and defined thickness is necessary. In this study, we use plasma treatments on the as-grown Mo surface prior to the CZTSe absorber formation, which consists of the deposition of stacked metallic layers and the annealing in selenium (Se) atmosphere. The plasma treatments include the application of a pure argon (Ar) plasma and a mixed argon-nitrogen (Ar-N) plasma. We observe a clear impact of the Ar plasma treatment on the MoSe thickness and interfacial morphology. With the Ar-N plasma treatment, a nitrided Mo surface can be obtained. Furthermore, we combine the Ar plasma treatment with the application of titanium nitride (TiN) as back-contact barrier and discuss the obtained results in terms of MoSe formation and solar cell performance, thus showing possible directions of back-contact engineering for CZTSe solar cells.
钼（Mo）是基于铜锌锡硒（CZTSe）的薄膜太阳能电池最常用的背接触材料。对于大多数制造方法，会形成厚度不受控制的界面二硒化钼（MoSe）层，其厚度范围从几十纳米到约1μm。为了改善CZTSe太阳能电池背接触界面的可控性，形成具有均匀且确定厚度的MoSe层是必要的。在本研究中，我们在形成CZTSe吸收层之前，对生长态的Mo表面进行等离子体处理，该处理包括堆叠金属层的沉积以及在硒（Se）气氛中退火。等离子体处理包括施加纯氩（Ar）等离子体和混合氩 - 氮（Ar - N）等离子体。我们观察到Ar等离子体处理对MoSe厚度和界面形态有明显影响。通过Ar - N等离子体处理，可以获得氮化的Mo表面。此外，我们将Ar等离子体处理与应用氮化钛（TiN）作为背接触势垒相结合，并从MoSe形成和太阳能电池性能方面讨论所得结果，从而展示了CZTSe太阳能电池背接触工程的可能方向。
