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Double Charge Polarity Switching in Sb‐Doped SnSe with Switchable Substitution Sites
Author(s) -
Yamamoto Chihiro,
He Xinyi,
Katase Takayoshi,
Ide Keisuke,
Goto Yosuke,
Mizuguchi Yoshikazu,
Samizo Akane,
Minohara Makoto,
Ueda Shigenori,
Hiramatsu Hidenori,
Hosono Hideo,
Kamiya Toshio
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202008092
Subject(s) - materials science , homojunction , doping , selenide , thermal conduction , tin , polarity (international relations) , chalcogen , vacancy defect , impurity , condensed matter physics , crystallography , optoelectronics , selenium , chemistry , physics , biochemistry , metallurgy , composite material , cell , organic chemistry
Tin mono‐selenide (SnSe) is one of the most promising thermoelectric materials; however, it experiences difficulty in controlling the carrier polarity, which is inevitable for realizing p‐n homojunction devices. Herein, double switching of charge polarity in (Sn 1− x Sb x )Se by varying x is reported; pure SnSe shows p‐type conduction, whereas the polarity of (Sn 1− x Sb x )Se switches to n‐type conduction for 0.005 < x < 0.05, and then re‐switches to p‐type conduction for x > 0.05. The major Sb substitution site switches from the Se (Sb Se ) to Sn site (Sb Sn ) with increasing x . Sb Sn (Sb 3+ at Sn 2+ ) works as a donor, but Sb Se (Sb 3− at Se 2− ) does not produce a hole because of the Sb–Sb dimer formation. The mechanism of double polarity switching is explained by native p‐type conduction in pure SnSe due to Sn‐vacancy formation, whereas (Sn 1− x Sb x )Se exhibits n‐type behavior due to conduction through the Sb Se impurity band formed above the valence band maximum, and finally re‐switches to weak p‐type, where the Fermi level approaches the midgap level between the Sb Se band and conduction band minimum. Clarification of the Sb doping mechanism will provide a crucial guide for developing more sophisticated doping routes for SnSe and high‐performance energy‐related devices.