Detection and Characterization of Trap Levels in Semiconducting Ceramics

半导体陶瓷中陷阱能级的检测和表征

• 批准号: 05453077
• 负责人: TAKATA Masasuke
• 金额: $ 4.48万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05453077/
• 关键词: PTCR; ICTS; Barium Titanate; PMN; Grain Boundary; Electron Capture; HIP; Zinc Oxide; 酸化

The degradation phenomenon in a ZnO varistor was investigated by means of isothermal capacitance transient spectroscopy (ICTS), paying special attention to the trap levels. From the analysis of ICTS signals before and after degradation, the interface trap levels were found to shift toward the conduction band, and their energetical distribution was broadened. The degradation phenomenon was related to the interface states of the grain boundaries.The PTCR effect in BaTiO_3 is a grain boundary effect caused by a two dimensional layr of acceptor states which attract electrons from the grain interior. The acceptor state density and the energy gap, Es, between the conduction band and the energy level of the acceptor states govern the PTCR-properties. The samples annealed at high Po_2 (10 MPa) had a higher Es than the samples annealed at lower Po_2 (0.1 MPa), leading to improved PTCR-properties. Based on this finding and results from the literature, a phenomenological PTCR model and an accompanying PTCR chart for acceptor-donor-codoped BaTiO_3 were proposed. The PTCR chart clarifies that acceptor dopant concentrations, oxidation time, and oxygen partial pressure during oxidation or cooling can be optimized simultaneously to obtain the best PTCR ceramics.

通过等温电容瞬态光谱 (ICTS) 研究了 ZnO 压敏电阻的退化现象，特别关注陷阱能级。通过对降解前后ICTS信号的分析，发现界面陷阱能级向导带移动，并且其能量分布变宽。这种退化现象与晶界的界面态有关。BaTiO_3中的PTCR效应是二维受主态层从晶粒内部吸引电子引起的晶界效应。受主态密度和导带与受主态能级之间的能隙 Es 决定了 PTCR 特性。在高 Po_2 (10 MPa) 下退火的样品比在较低 Po_2 (0.1 MPa) 下退火的样品具有更高的 Es，从而改善了 PTCR 性能。基于这一发现和文献结果，提出了受体-供体共掺杂 BaTiO_3 的唯象 PTCR 模型和随附的 PTCR 图。 PTCR图表阐明了受主掺杂剂浓度、氧化时间和氧化或冷却过程中的氧分压可以同时优化以获得最佳的PTCR陶瓷。

项目成果

M.Takata: "Relationship between Degradation Phenomenon and Trap Levels in a ZnO Varistor" Bull.Amer.Ceram.Soc.72. 96-98 (1993)

M.Takata：“ZnO 压敏电阻中的降解现象与陷阱水平之间的关系”Bull.Amer.Ceram.Soc.72。

Y.Watanabe,H.Endo,H.Semba and M.Takata: "Electronic Structure and Optical Non-linarity of Tin Oxide Thin Films" J.Non.Cryst.Solids. 178. 84-90 (1994)

Y.Watanabe、H.Endo、H.Semba 和 M.Takata：“氧化锡薄膜的电子结构和光学非线性”J.Non.Cryst.Solids。

T.Okamoto,B.Huybrechts and M.Takata: "Electric Field Sensitive Moving Hot Spot in GdBa_2Cu_3O_7-δ Ceramics" Jpn.J.Appl.Phys.33(9A). L1212-14 (1994)

T.Okamoto、B.Huybrechts 和 M.Takata：“GdBa_2Cu_3O_7-δ 陶瓷中的电场敏感移动热点”Jpn.J.Appl.Phys.33(9A) (1994)。

B.Huybrechts et.al: "Proposed Phenomenological PTCR Model and Accompanying Phenomenological PTCR Chart" J.Am.Ceram.Soc.77. 286-88 (1994)

B.Huybrechts 等人：“提议的现象学 PTCR 模型和随附的现象学 PTCR 图”J.Am.Ceram.Soc.77。

B.Huybrechts, K.Ishizaki and M.Takata: ""Influence of High Oxygen Partial Pressure on the Positive Temperature Coefficient of Mn-doped Ba_<0.8>Sr_<0.2>TiO_3"" J.Eur.Ceram.Soc.11(5). 395-400 (1993)

B.Huybrechts、K.Ishizaki 和 M.Takata：“高氧分压对 Mn 掺杂 Ba_<0.8>Sr_<0.2>TiO_3 正温度系数的影响”J.Eur.Ceram.Soc.11(