Spin polarized electron source

外国特許コード	F120006260
整理番号	J1018-02WO
掲載日	2012年2月21日
出願国	欧州特許庁（ＥＰＯ）
出願番号	09724694
公報番号	2270832
公報番号	2270832
出願日	平成21年3月24日(2009.3.24)
公報発行日	平成23年1月5日(2011.1.5)
公報発行日	平成28年2月10日(2016.2.10)
国際出願番号	JP2009001304
国際公開番号	WO2009119074
国際出願日	平成21年3月24日(2009.3.24)
国際公開日	平成21年10月1日(2009.10.1)
優先権データ	2009JP001304 (2009.3.24) WO 特願2008-079292 (2008.3.25) JP
発明の名称 （英語）	Spin polarized electron source
発明の概要（英語）	To provide implement a spin-polarized electron generating device having high spin polarization and high external quantum efficiency while allowing a certain degree of freedom in selecting materials of a substrate, a buffer layer, and a strained superlattice layer. In a spin-polarized electron generating device having a substrate, a buffer layer, and a strained superlattice layer formed on the buffer layer, an intermediate layer formed of a crystal having a lattice constant greater than that of a crystal used to form the buffer layer intervenes between the substrate and the buffer layer. With this arrangement, tensile strain causes cracks to be formed in the buffer layer in a direction perpendicular to the substrate, whereby the buffer layer has mosaic-like appearance. As a result, glide dislocations in an oblique direction do not propagate to the strained superlattice layer to be grown on the buffer layer, thereby improving crystallinity of the strained superlattice layer. Accordingly, spin polarization of excited electrons and external quantum efficiency of polarized electrons improve.
特許請求の範囲（英語）	[claim1] 1. A spin-polarized electron generating device comprising a substrate (10-12), a buffer layer (30-32), and a strained superlattice layer (40-42) formed on the buffer layer, wherein an intermediate layer (20-22) formed of a crystal having a lattice constant greater than that of a crystal of the buffer layer is disposed between the substrate and the buffer layer, characterized in that the buffer layer (30-32) has cracks formed therein in a direction perpendicular to the substrate (10-12) by the effect of tensile strain. [claim2] 2. A spin-polarized electron generating device according to claim 1, wherein the substrate is formed of GaP; the buffer layer is formed of any one selected from a group consisting of GaAs xP 1-x (0 <= x <= 1), Ga yIn 1-yP (0 <= y <= 1), and Ga zIn 1-zAs (0 <= z <= 1); and the intermediate layer is formed of a binary, ternary, quaternary, or quinary compound AlGaInAsP having a lattice constant greater than that of the buffer layer. [claim3] 3. A spin-polarized electron generating device according to claim 2, wherein the intermediate layer is formed of GaAs. [claim4] 4. A spin-polarized electron generating device according to claim 1, wherein the substrate is formed of GaAs; the buffer layer is formed of any one selected from a group consisting of GaAs xP 1-x (0 <= x <= 1), Ga yIn 1-yP (0 <= y <= 1), and Ga zIn 1-zAs (0 <= z <= 1); and the intermediate layer is formed of a binary, ternary, quaternary, or quinary compound AlGaInAsP having a lattice constant greater than that of the buffer layer. [claim5] 5. A spin-polarized electron generating device according to claim 4, wherein the intermediate layer is formed of InAs. [claim6] 6. A spin-polarized electron generating device according to claim 1, wherein the substrate is formed of GaN; the buffer layer is formed of any one selected from a group consisting of Al xGa 1-xN (0 <= x <= 1) and Ga yIn 1-yN (0 <= y <= 1); and the intermediate layer is formed of a binary, ternary, or quaternary compound AlGaInN having a lattice constant greater than that of the buffer layer. [claim7] 7. A spin-polarized electron generating device according to claim 6, wherein the intermediate layer is formed of InN. [claim8] 8. A spin-polarized electron generating apparatus (100) comprising a spin-polarized electron generating device according to any one of claims 1 to 7. [claim9] 9. A spin-polarized electron generating apparatus according to claim 8, wherein the spin-polarized electron generating apparatus is an electron microscope.
出願人（英語）	JAPAN SCIENCE AND TECHNOLOGY AGENCY
発明者（英語）	UJIHARA TORU JIN XIUGUANG TAKEDA YOSHIKAZU NAKANISHI TSUTOMU YAMAMOTO NAOTO SAKA TAKASHI KATOU TOSHIHIRO
国際特許分類(IPC)	H01J  37/073     電界放出，光電子放出，または２次電子放出による電子源を用いる電子銃 G21K   1/00      粒子または電離放射線の取扱い装置，例．集束または減速 H01J   1/34      光電子放射陰極 H01J   3/02      電子銃