Thin Film and Bulk Syntheses of Zn-IV-N2 Nitrides

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04500
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: Chubu University
• Principal Investigator: YAMADA Naoomi 中部大学, 工学部, 教授 (50398575)
• Co-Investigator(Kenkyū-buntansha): 川村 史朗 国立研究開発法人物質・材料研究機構, 機能性材料研究拠点, 主任研究員 (80448092)
• Research Collaborator: CAO Xiang
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 窒化物半導体 / 疑似III族窒化物 / 太陽電池 / バンドギャップ / 有効質量

Outline of Final Research Achievements

We made efforts to synthesize a novel pseudo III-nitrides, Zn-IV-N2 (IV = Sn and Ge) in the forms of thin films and bulk. In particular, we focused on ZnSnN2 that have hardly been investigated from the experimental point of views. We succeeded the synthesis of ZnSnN2 in the powder form for the first time, employing metathesis reaction under high pressure. Using the powder samples, the crystal structure was revealed to be wurtzite-type structure. Furthermore, taking advantage of this finding, epitaxial films were grown on the (111) plane of YSZ to investigate its intrinsic properties. From the analysis of the optical properties, the bandgap and conduction-band effective mass were derived to be Eg = 1.0 eV and mc* = 0.37m0 (m0 denotes the free electron mass). Moreover, we found that substitution of Zn by Mg can increase the bandgap. Optimizing Mg concentration may lead to Eg = 1.4 eV that is the ideal value for photovoltaic absorber.

Free Research Field

固体化学

Academic Significance and Societal Importance of the Research Achievements

疑似III族窒化物であるZn-IV-N2は，現行のIII族窒化物の安価な代替材料として検討されていたが，結晶構造やバンドギャップ，電子の有効質量などが不明な点が多かった。そのため，デバイス応用を考える段階に至っていなかった。本研究では，Zn-IV-N2の中で，全くと言ってよいほど研究されてこなかったZnSnN2の固有物性の一端を明らかにできた。本研究によって，Zn-IV-N2系ならびにそれらの混晶のデバイス応用へ向けた基礎的な知見が得られたものと思われる．