Analysis of Cs/GaAs NEA surface by XAFS

被引：3

作者：

Tsubota, K. ^{[1
]}

Tabuchi, M. ^{[2
]}

Nishitani, T. ^{[2
]}

Era, A. ^{[1
]}

Takeda, Y. ^{[2
]}

机构：

[1] Nagoya Univ, Grad Sch Engn, Nagoya, Aichi 4648601, Japan

[2] Nagoya Univ, Res Ctr, Nagoya, Aichi 4648601, Japan

来源：

15TH INTERNATIONAL CONFERENCE ON X-RAY ABSORPTION FINE STRUCTURE (XAFS15) | 2013年 / 430卷

关键词：

D O I：

10.1088/1742-6596/430/1/012079

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

By exposing a GaAs surface to Cs and O-2, a surface which is called negative electron affinity (NEA) surface can be obtained where the vacuum level shifts lower than the bottom of GaAs conduction band. The Cs/GaAs NEA surface has been attracting great attention in recent years, because of its availability for a highly functional electron source which can be controlled by excitation light. In this work, XAFS and X-ray fluorescence measurements were conducted for Cs/GaAs NEA surface prepared on GaAs (001) and (110) substrates. As the result, As and O were considered as near neighbor atoms of center Cs for both of the samples. Most of Cs formed some kind of Cs-oxide and the Cs atoms at interface between Cs-oxide and GaAs were observed as forming Cs-As bond. Taking account of the ratios of coordination numbers and the fluorescence X-ray yield, the Cs-oxide on GaAs (001) surface forms island like structure in which the body/interface ratio is large, and the Cs-oxide on GaAs (110) surface forms layer like structure in which the body/interface ratio is small.

引用

页数：5

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