Transmission Electron Microscopy And Electron Energy-Loss Spectroscopy Studies Of Hole-Selective Molybdenum Oxide Contacts In Silicon Solar Cells

Keywords

electron energy-loss spectroscopy (EELS); hole-selective; molybdenum oxide (MoO ) x; silicon; transmission electron microscopy (TEM)

Abstract

In this study, substochiometric hole-selective molybdenum oxide (MoOx) contacts in crystalline silicon (c-Si) solar cells were investigated by a combination of transmission electron microscopy (TEM) and spatially resolved electron energy-loss spectroscopy (SR-EELS). It was observed that a ≈ 4 nm SiOx interlayer grows at the MoOx/c-Si interface during the evaporation of MoOx over a c-Si substrate. SR-EELS analyses revealed the presence of a 1.5 nm diffused MoOx/indium tin oxide (ITO) interface in both as-deposited and annealed samples. Moreover, the presence of a 1 nm thin layer with a lower oxidation state of Mo was detected at the SiOx/MoOx interface in an as-deposited state, which disappears upon annealing. Overall, it was evident that no hole-blocking interlayer is formed at the MoOx/ITO interface during annealing and homogenization of the MoOx layer takes place during the annealing process. Furthermore, device simulations revealed that efficient hole collection is dependent on MoOx work function and that reduction in the work function of MoOx results in loss of band bending and negatively impacts hole selectivity.

Publication Date

11-20-2019

Publication Title

ACS Applied Materials and Interfaces

Volume

11

Number of Pages

43075-43080

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/acsami.9b12703

Socpus ID

85074917561 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85074917561

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