【公開日：2023.08.01】【最終更新日：2023.05.21】
課題データ / Project Data
課題番号 / Project Issue Number
22NU0071
利用課題名 / Title
Cu2ZnSnSe4薄膜合成におけるナノ構造及び核生成現象その場観察
利用した実施機関 / Support Institute
名古屋大学 / Nagoya Univ.
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion（副 / Sub）高度なデバイス機能の発現を可能とするマテリアル/Materials allowing high-level device functions to be performed
キーワード / Keywords
電子顕微鏡/Electron microscopy,質量分析/Mass spectrometry,ナノフォトニクスデバイス/ Nanophotonics device,太陽電池/ Solar cell
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Leifer Klaus
所属名 / Affiliation
ウプサラ大学
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
Sharath Kumar,Edgardo Saucedo
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
武藤俊介,荒井重勇
利用形態 / Support Type
（主 / Main）共同研究/Joint Research（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Solar cells are in the focus
of efforts to reduce CO2 emissions as well as to build a more
sustainable world. Despite of the tremendous progress in solar cell development
and fabrication, to date, most solar cells contain rare and toxic elements.
Therefore, kesterite solar cells like Cu2ZnSnSe4 and Cu2ZnSnS4
containing only earth abundant elements, are an excellent candidate for
building sustainable solar cells. The increase in kesterite solar cell
efficiency over the last decade is considerable, though a detailed
understanding of the evolution of the structure in the synthesis process has
not yet been addressed by microscopy techniques. A nanoscopic analysis of grain
nucleation, growth and diffusion pathways using transmission electron
microscopy (TEM) has therefore a high potential to foster understanding of the
synthesis process as well as contribute to the improvement of such solar cells.
Nagoya University is equipped
with a unique in-situ TEM enabling us not only to observe the structural and
chemical evolution during synthesis of kesterites but also, due to the
extremely sensitive mass spectrometer, to analyze the
materials being absorbed and desorbed on the sample. This enables us to
understand how the growth parameters such as temperature and composition of the
original thin metallic film impact the growth of the kesterite layers.
実験 / Experimental
The synthesis of those solar cells starts from either alloys or multilayers containing the metallic elements. These thin coatings are annealed in Se atmosphere at heat ramps above 300°C. In this process, the Se will alloy first with Ge, and then, after onset of diffusion, homogeneous Cu2ZnSnSe4 grains of a size of the order of micron are formed. We have carried out first precursor experiments at Nagoya University to demonstrate the feasibility of such in-situ experiment and could setup the experiment in the TEM, determine the temperature range at which Se gets absorbed in the sample, observe the first nucleation of grains and carry out EELS analysis at elevated temperature. In this project, we would like to study: Grain growth at different temperatures starting at about 300°C.
結果と考察 / Results and Discussion
The entire experiment is
carried out using Reaction Science HVSTEM (JEM1000K RS). 1) around
450-500degrees, high Ar pressure: the elements are present in separate layers,
then inter-diffusion more or less stoichiometric grains of the size of a few
100nm typically. 2) around 550 degrees, high Ar pressure, massive
Se out-diffusion is compensated by Se containing vapor, carrier gas Argon.
Here, the quality of grain boundaries improves and further grain growth.
✓ In the thicker areas, total signal high, plural scattering
makes comparison Cu/Zn difficult
✓ But in general, Zn and Cu are not homogeneously
distributed
✓ Concentration varies on a typical scale of 100nm
図・表・数式 / Figures, Tables and Equations
Fig. 1 Dark contrasts of size of 20-50nm appear.
Fig. 2 Cu, Zn, Se clearly identified (Sn also seen, but not in the energy region displayed here).
Fig. 3 Elemental distributions after annealing in TEM.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
本研究は、未来材料・システム研究所・武藤俊介教授との共同研究として実施された。
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件