Doping and solid solution in SnS: introduction of cations using metals with low melting point as a reaction field

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02495
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26060:Metals production and resources production-related
• Research Institution: Kyoto University
• Principal Investigator: Nose Yoshitaro 京都大学, 工学研究科, 准教授 (00375106)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 化学ポテンシャル制御 / 反応場 / 二次元材料 / 固溶体 / ドーピング / pn反転

Outline of Final Research Achievements

In this study, we demonstrated to obtain the n-type conduction of SnS and to control the bandgap using (Ge,Sn)S solid solution by controlling the chemical potential in liquid phase containing Sn in equilibrium with SnS. In the former case, the change of conduction type from p to n was observed at the Sb composition of 0.02 mol% in the SnS crystal. As we planned in this study, n-type conduction was confirmed for the first time in cation doping of SnS by realizing a chemical potential environment different from the conventional one. On the other hand, the addition of Bi as a fourth element to the system results the equilibrium of (Ge,Sn)S solid solution with liquid phase. The solid solution crystals with a controlled band gap were obtained by evaporation based on the equilibrium.

Free Research Field

結晶成長

Academic Significance and Societal Importance of the Research Achievements

本研究では従来困難であった，カチオンドープによるSnSのn型伝導化に初めて成功した。これにより，太陽電池におけるホモpn接合の実現などに対して重要な知見を与える。また，固溶体形成に関しては，プロセスの低温化という制約に対して，液相との平衡と分留を組み合わせることで解決策を提示した。いずれも，目的の結晶と熱力学的平衡にある液相の化学ポテンシャルを制御するという考え方に基づくものである。このような冶金的な考え方を半導体プロセスに適用することで，新奇の材料，およびプロセス開発に繋がることが期待できる。