Influence of Sulfur Evaporation during or after KF-Post Deposition Treatment On Cu(In,Ga)Se2/CdS Interface Formation

• Published in: ACS applied materials & interfaces 2020-10, Vol.12 (41), p.46953-46962
• Main Authors: Harel, Sylvie, Arzel, Ludovic, Lepetit, Thomas, Zabierowski, Pawel, Barreau, Nicolas
• Format: Article
• Language: English
• Subjects: Surfaces, Interfaces, and Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c12455

This work investigates the impact of the elemental sulfur evaporation during or after KF-post deposition treatment (KF-PDT) on the resulting Cu­(In,Ga)­Se2/chemical bath deposited­(CBD)-CdS interface. Chemical composition of the various interfaces were determined through Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger spectroscopy (XAES). Cu­(In,Ga)­Se2 absorber which experienced KF-PDT in selenium atmosphere (KSe sample) exhibits the formation of the well-reported In–Se based topping layer. Additional exposure to elemental sulfur, resulting in KSe+S sample, induces the partial sulfurization of this overlayer and/or of the absorber. After short immersion into the CdS bath, the resulting In-rich surfaces of KSe and KSe+S are likely to turn into few atomic layers of Cd–In–(Se/S)–O whose [S]/[Se]+[S] ratio and O content depend on their respective post deposition treatment. In contrast, KF-PDT performed in S atmosphere does not show an In-rich surface, making the early stage of CdS growth similar to that observed on untreated CIGSe.