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Sulfurization Growth and HCl Etching Processes for Cubic‐Phase SnS Thin Films
Author(s) -
Tosuke Taichi,
Sugiyama Mutsumi
Publication year - 2019
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201800750
Subject(s) - orthorhombic crystal system , materials science , etching (microfabrication) , phase diagram , phase (matter) , layer (electronics) , thin film , analytical chemistry (journal) , crystallography , nanotechnology , chemistry , crystal structure , organic chemistry , chromatography
The synthesis of cubic‐phase SnS thin films using a sulfurization technique, in particular, the relationship between sulfurization conditions and extra phase contamination such as orthorhombic SnS, Sn 2 S 3 , or SnS 2 is investigated. In case of SnS films sulfurized for 70–90 min, both cubic and orthorhombic SnS‐related diffractions are observed. Sulfurization time longer than 120 min, orthorhombic SnS and SnS 2 ‐related diffractions are observed because the S vapor reacts with the SnS layer and forms a stable extra phase as SnS 2 . A single phase of cubic SnS is obtained via 18%‐HCl‐solution etching for 90 min without heating. Since the formation energy of cubic SnS is the same as that of orthorhombic SnS, obtaining single‐phase cubic SnS is difficult by optimizing a sulfurization and/or post‐thermal process. Moreover, because the band discontinuity of CdS/cubic SnS speculates a TYPE‐II band diagram, highly efficient SnS solar cells cannot be realized using CdS as an n‐type layer.