Analysis of quantum efficiency improvement in spin-polarized photocathode

Xiuguang Jin, Shunsuke Ohki, Tomoki Ishikawa, Atsushi Tackeuchi, Yosuke Honda

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

GaAs/GaAsP strain-compensated superlattices (SLs) were developed for spin-polarized photocathode applications. High crystal quality was maintained with SL thicknesses up to 720 nm (90-pairs); however, the quantum efficiency (QE) did not increase linearly with the SL thickness but became saturated starting from an SL thickness of 192 nm (24-pairs). Time-resolved photoluminescence measurements revealed that the carrier lifetime in the GaAs/GaAsP strain-compensated SL was as short as 20.5 ps at room temperature, which causes the elimination of photoexcited electrons before emission. A simulation based on a diffusion model was implemented to quantitatively evaluate the effect of the carrier lifetime on the QE. The simulation results were in good agreement with the experimental results and demonstrate that a carrier lifetime of over 120 ps is required for a two-fold improvement of the QE.

Original languageEnglish
Article number164501
JournalJournal of Applied Physics
Volume120
Issue number16
DOIs
Publication statusPublished - 2016 Oct 28

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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