Optical properties of Mn4+ ions in GaN:Mn codoped with Mg acceptors

TL;DR

This study investigates how Mg acceptors influence the optical properties of Mn4+ ions in GaN, revealing stabilized Mn4+ charge states and distinct photoluminescence features at 1 eV related to intra-center transitions.

Contribution

It provides new insights into the stabilization of Mn4+ ions in GaN through Mg codoping and characterizes their optical emission properties and complex centers.

Findings

Mg addition quenches Mn-related PL at 1.3 eV

Sharp PL peaks at 1 eV are observed in codoped samples

Multiple Mn4+ complex centers are identified

Abstract

The optical properties of Mn-Mg codoped epitaxial GaN were studied. Addition of Mg acceptors quenches the weak manganese-related photoluminescence (PL) band at 1.3 eV in GaN:Mn and a series of sharp PL peaks are observed at 1 eV in codoped epilayers. The change in PL spectra indicates that Mg addition stabilizes the Mn4+ charge state by decreasing the Fermi level. The 1 eV PL peaks are tentatively attributed to intra center transitions involving Mn4+ ions. Spin allowed 3d-shell 4T2-4T1 transitions and their phonon replicas are involved. The relative intensities of the sharp peaks are strongly dependent on the excitation wavelength, indicating the optically active Mn4+ centers involved in the separate peaks are different. The temperature dependence of the PL spectrum suggests the presence of at least three distinct Mn4+ complex centers.