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Atomic-Layer-Deposited TiOx Nanolayers Function as Efficient Hole-Selective Passivating Contacts in Silicon Solar Cells

 
: Matsui, T.; Bivour, M.; Hermle, M.; Sai, H.

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ACS applied materials & interfaces 12 (2020), Nr.44, S.49777-49785
ISSN: 1944-8244
ISSN: 0013-936X
ISSN: 1944-8252
Englisch
Zeitschriftenaufsatz
Fraunhofer ISE ()

Abstract
Titanium oxide (TiOx) has recently emerged as an electron-selective passivating contact for solar cell and semiconductor device applications. The mechanism behind this function has been attributed to the lower energy barrier for electrons than holes at the TiOx/semiconductor interface. Here we report an antithetic function of TiOx nanolayers (∼5 nm), which were grown by atomic layer deposition (ALD) on either planar or textured crystalline silicon (Si) without a buffer layer, acting as efficient hole-selective contacts with excellent surface passivation. We demonstrate the proof-of-concept solar cells with power conversion efficiencies above 20% with both n- and p-Si absorbers. We show that the elemental composition in the TiOx/Si interfacial layers (TiOxSiy:H and SiOx:H), which can be manipulated by the ALD process and the post-treatments such as exposure to atomic hydrogen and supply of oxygen during annealing, is a key in the efficient hole extraction and surface passivation. This new hole-selective passivating contact opens opportunities for replacing the widely used heterocontacts and dielectric-passivation layers in various device applications.

: http://publica.fraunhofer.de/dokumente/N-639946.html