Strain-Compensated AlInGaAs-GaAsP Superlattices for Highly-Polarized Electron Emission

TL;DR

This paper investigates strain-compensated AlInGaAs-GaAsP superlattice photocathodes, demonstrating high polarization and quantum yield, and analyzes factors affecting polarization losses, highlighting the potential of strain engineering for advanced electron sources.

Contribution

It introduces a strain compensation technique in superlattice photocathodes that achieves near-best polarization and quantum yield results, advancing the design of spin-polarized electron emitters.

Findings

Maximum polarization and quantum yield close to best reported values.

Strain compensation effectively enhances electron emission properties.

Analysis identifies key parameters influencing polarization losses.

Abstract

Spin-polarized electron emission from the first superlattice photocathodes developed with strain compensation is investigated. An opposite strain in the quantum well and barrier layers is complished using an InAlGaAs/GaAsP superlattice structure. The measured values of maximum polarization and quantum yield for the structure with a 0.18 um-thick working layer are close to the best results reported for any strained superlattice photocathode structure, demonstrating the high potential of strain compensation for future photocathode applications. An analysis of the photoemission spectra is used to estimate the parameters responsible for the polarization losses.