Emission and life characteristics of thin film top-layer scandate cathode and diffusion of Sc2O3 and W

被引：38

作者：

Uda, E ^{[1
]}

Nakamura, O ^{[1
]}

Matsumoto, S ^{[1
]}

Higuchi, T ^{[1
]}

机构：

[1] Toshiba Corp, Elect Tubes & Devices Div, Isogo Ku, Yokohama, Kanagawa 2358522, Japan

来源：

APPLIED SURFACE SCIENCE | 1999年 / 146卷 / 1-4期

关键词：

thermionic electron emission; scandate cathode; thin film; bulk diffusion; scandium oxide; tungsten;

D O I：

10.1016/S0169-4332(99)00067-7

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We investigated top-layer scandate cathodes, which are the most promising of scandate cathodes. Among the cathodes which we prepared with a layer of various thickness, the best pulse emission of 80 A/cm(2) at 1300 K was recorded with cathodes having a top layer consisting of a Sc2O3 layer 2 nm thick on a W layer 8 nm thick. The emission variation of these cathodes was evaluated in life tests. The life characteristics were good in both diode and triode evaluation. We also determined diffusion coefficients of W and Sc2O3 with unporous W pellets covered with a Sc2O3 and W layer. Variations of surface concentrations of these pellets during life tests were measured using Auger electron spectroscopy. The diffusion coefficients were 6.4 x 10(-19), 1.0 x 10(-18), and 1.6 x 10(-18) cm(2)/s at 1220 K, 1300 K, and 1370 K. Chemical states of O, Sc, and W are discussed based on detailed analysis of Auger electron spectra. (C) 1999 Elsevier Science B.V. All rights reserved.

引用

页码：31 / 38

页数：8

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