Enhanced annealing effect in an oxygen atmosphere on Ga1−xMnxAs

Abstract

Articles you may be interested inEffect of low-temperature annealing on the electronic-and band-structures of (Ga,Mn)As epitaxial layers

Enhanced annealing, high Curie temperature, and low-voltage gating in (Ga,Mn)As: A surface oxide control study

“…8,10,11,12,13,14,15,16,17 Figures 1 and 2 provide a resolution to this question and show that it has important consequences for the efficiency of the post-growth optimization of magnetic properties of the material. T c = 180 K represents an increase of the record Curie temperature achieved in (Ga,Mn)As to date 6 by 7 K and is the highest T c reported for uniform, carrier-mediated (III,Mn)V ferromagnet.…”

“…), the diffusion of the interstitial Mn towards the (Ga,Mn)As free surface is inhibited by the formation of an electrostatic barrier. 8,10,11,12,14,15 From this perspective the key role of the surface oxide in the annealing process is plausible as it might prevent the Mn-ions and free oxygen from interacting with each other. It is a generic feature, related to the shorter (by ∼20%) metaloxygen bond length compared to GaAs, less interstitial space, and amorphous structure, that the impurity diffusion channels through the oxide are effectively blocked.…”

Annealing-induced enhancement of ferromagnetism and nanoparticle formation in the ferromagnetic semiconductorGeFe

“…11,12 In III-V-based FMS (Ga,Mn)As, post-growth annealing is known to be a powerful technique to improve the T C by removing the interstitial Mn atoms from the (Ga,Mn)As layer. 13,14 Here, we investigate the annealing effect on GeFe in order to enhance the ferromagnetism of GeFe.…”

Solid Phase Epitaxy of Ferromagnetic MnAs Layer and Quantum Dots on Annealed GaMnAs

“…The Mn interstitials counteract the stability of the ferromagnetic state by acting as double donors (thereby compensating the valence band holes responsible for ferromagnetic ordering), and by directly coupling antiferromagnetically to Mn in Ga substitutional sites (which provide both the magnetic moments and valence band holes). It has been reported by several groups [1][2][3][4][5] that by post-growth annealing the T c of GaMnAs can be significantly increased, up to 160-170 K, whereas in as-grown material it is usually below 100-110 K. It is generally accepted that PGA changes the defect structure of GaMnAs. So far it was proposed, and partially verified experimentally [6,7] that PGA mainly affects the Mn I defects.…”

“…It is currently debated which PGA procedures lead to the best results [1][2][3][4][5][6][10][11][12][13], however it is important to note that GaMnAs is a metastable compound and by extended annealings at temperatures exceeding 280-300…”