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2D Ca 3 Sn 2 S 7 Chalcogenide Perovskite: A Graphene‐Like Semiconductor with Direct Bandgap 0.5 eV and Ultrahigh Carrier Mobility 6.7 × 10 4 cm 2 V −1 s −1
Author(s) -
Du Juan,
Shi Junjie
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201905643
Subject(s) - materials science , chalcogenide , graphene , band gap , semiconductor , perovskite (structure) , electron mobility , optoelectronics , narrow gap semiconductor , nanotechnology , crystallography , chemistry
Graphene, a star 2D material, has attracted much attention because of its unique properties including linear electronic dispersion, massless carriers, and ultrahigh carrier mobility (10 4 –10 5 cm 2 V −1 s −1 ). However, its zero bandgap greatly impedes its application in the semiconductor industry. Opening the zero bandgap has become an unresolved worldwide problem. Here, a novel and stable 2D Ruddlesden–Popper‐type layered chalcogenide perovskite semiconductor Ca 3 Sn 2 S 7 is found based on first‐principles GW calculations, which exhibits excellent electronic, optical, and transport properties, as well as soft and isotropic mechanical characteristics. Surprisingly, it has a graphene‐like linear electronic dispersion, small carrier effective mass (0.04 m 0 ), ultrahigh room‐temperature carrier mobility (6.7 × 10 4 cm 2 V −1 s −1 ), Fermi velocity (3 × 10 5 m s −1 ), and optical absorption coefficient (10 5 cm −1 ). Particularly, it has a direct quasi‐particle bandgap of 0.5 eV, which realizes the dream of opening the graphene bandgap in a new way. These results guarantee its application in infrared optoelectronic and high‐speed electronic devices.