Analyses and Excess Oxygen Investigations by Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy at AlOx/Si Interfaces in Passivated Emitter and Rear Solar Cells. Issue 17 (14th July 2021)

• Record Type: Journal Article
• Authors: Naumann, Volker; Schütze, Matthias; Hähnel, Angelika; Lange, Stefan; Müller, Alexander; Hagendorf, Christian
• Is Part Of: Physica status solidi. Volume 218:Issue 17(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-14
• Subjects: electron energy loss spectroscopy -- excess oxygen -- passivated emitter and rear solar cells (PERC) -- passivation layers -- transmission electron microscopy; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202100223
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Progressive optimization of the surface passivation of Si solar cells requires access to the elemental composition and chemical bonding characteristics of ultrathin layers and buried interfaces on textured or structured surfaces. The passivation of the rear side of passivated emitter and rear solar cells, for instance, can be realized through AlO x /SiN x stacks, which are known to provide an additional field effect passivation on top of the chemical surface passivation. Herein, transmission electron microscopy is used at locally prepared cross‐sections of such stacks. Electron energy loss spectroscopy is used to extract depth‐resolved information of elemental composition and chemical bonding at nanometer scale. With this, the interfacial excess O fraction, which is crucial for the field effect passivation, is successfully determined for the first time for AlO x passivation layer systems on industrially produced Si solar cells. Abstract : The interface between silicon and the dielectric passivation layer is investigated by scanning transmission electron microscopy combined with electron energy loss spectroscopy at cross‐sectional, lamellar samples prepared from the rear side of silicon solar cells. The acquired spectra of the interface region are evaluated regarding attribution of oxygen to the different phases, proving the presence of silicon oxide and excess oxygen.