Improvement of Cu2ZnSnS4 thin film morphology using Cu–Zn–Sn–O precursor fabricated by sputtering

• Published in: Current applied physics 2013, 13(9), , pp.1861-1864
• Main Authors: Ishino, Ryo, Fukushima, Kazuhiro, Minemoto, Takashi
• Format: Article
• Language: English
• Subjects: Copper; COPPER SULFIDE; crystal structure; Cu2ZnSnS4; CZT; DEPOSITION; FABRICATION; glass; Morphology; Oxide precursor; oxygen; Partial pressure; photovoltaic cells; physics; Precursors; PRESSURE; Solar cell; SPUTTERING; Thin film; THIN FILMS; 물리학
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2013.06.021

The new precursor of Cu–Zn–Sn–O (CZTO) was proposed for Cu2ZnSnS4 (CZTS) thin film fabrication to improve film morphology. The CZTS thin film grown from Cu–Zn–Sn (CZT) precursors has many bumps. We deposited CZTO precursors on Mo/soda-lime glass (SLG) substrates by RF sputtering using a CZT (Cu:Zn:Sn = 2:1:1) target in Ar and O2 atmosphere at various O2 partial pressures (0%, 5%, 17% and 20%). Subsequently, the CZTO precursors were sulfurized in Ar and S atmosphere to fabricate CZTS thin films. The CZTO precursors were amorphous. The morphology of the CZTS thin films was improved by the CZTO precursors. All of the CZTS films fabricated in this study had the same crystal structure. Composition analysis revealed that 50% of O were detected in the CZTO precursor, but O was not detected after sulfurizing process, indicating that O was substituted by S. The CZTS thin film from the CZTO precursor fabricated at O2 partial pressure of 20% had similar composition for solar cell absorber. •Cu–Zn–Sn–O precursors were used to improve morphologies of Cu2ZnSnS4 thin films.•Cu–Zn–Sn–O precursors were prepared by sputtering in Ar and O2 atmosphere.•Cu2ZnSnS4 thin films from Cu–Zn–Sn precursors had many bumps.•Cu2ZnSnS4 thin films from Cu–Zn–Sn–O precursors had flat surface.