Giant spin-dependent photo-conductivity in GaAsN dilute nitride semiconductor

TL;DR

This paper presents a combined theoretical and experimental investigation of spin-dependent photoconductivity in GaAsN, revealing how magnetic fields and recombination processes influence electron spin polarization and photoconductivity.

Contribution

It introduces a comprehensive rate equation model that captures the spin-dependent recombination dynamics and reproduces experimental observations in GaAsN semiconductors.

Findings

Photoconductivity shows a Hanle-type curve under magnetic fields.

Electron spin polarization exhibits two superimposed Lorentzian curves.

The model accurately reproduces photoluminescence and photocurrent features.

Abstract

A theoretical and experimental study of the spin-dependent photoconductivity in dilute Nitride GaAsN is presented. The non linear transport model we develop here is based on the rate equations for electrons, holes, deep paramagnetic and non paramagnetic centers both under CW and pulsed optical excitation. Emphasis is given to the effect of the competition between paramagnetic centers and non paramagnetic centers which allows us to reproduce the measured characteristics of the spin-dependent recombination power dependence. Particular attention is paid to the role of an external magnetic field in Voigt geometry. The photoconductivity exhibits a Hanle-type curve whereas the spin polarization of electrons shows two superimposed Lorentzian curves with different widths, respectively related to the recombination of free and trapped electrons. The model is capable of reproducing qualitatively and quantitatively the most important features of photoluminescence and photocurrent experiments and is helpful in providing insight on the various mechanisms involved in the electron spin polarization and filtering in GaAsN semiconductors.