Spin polarized electron source
| Foreign code | F120006260 |
|---|---|
| File No. | J1018-02WO |
| Posted date | Feb 21, 2012 |
| Country | EPO |
| Application number | 09724694 |
| Gazette No. | 2270832 |
| Gazette No. | 2270832 |
| Date of filing | Mar 24, 2009 |
| Gazette Date | Jan 5, 2011 |
| Gazette Date | Feb 10, 2016 |
| International application number | JP2009001304 |
| International publication number | WO2009119074 |
| Date of international filing | Mar 24, 2009 |
| Date of international publication | Oct 1, 2009 |
| Priority data |
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| Title | Spin polarized electron source |
| Abstract |
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. |
| Scope of claims |
[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. |
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| IPC(International Patent Classification) |
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Contact Information for " Spin polarized electron source "
- Japan Science and Technology Agency Department of Intellectual Property Management
- URL: http://www.jst.go.jp/chizai/
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