Impact of Manganese incorporation on the structural and magnetic properties of MOCVD-grown Ga1−xMnxN

Kane, Matthew H.; Ali, Asghar; Straßburg, Martin; Song, Qi; Payne, Adam; Summers, Christopher J.; Zhang, Z. John; Dietz, N.; Ferguson, Ian T.

doi:10.1557/proc-831-e9.4

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…The Mn 4-x Ga x N 1-y series is of considerable interest relative to the ferromagnetic behavior of these materials. This materials system has been shown to be one of the key decomposition products under annealing or non-optimal growth of these compounds, [20,21] and due to Ga-Mn site disorder, can result in a ferromagnetic metallic perovskite phase with Curie temperatures ranging from 270 K to 743 K [22]. Similar Curie temperatures have been reported in the references, and this phase has a structure that is commensurate with the wurtzite lattice [23].…”

Section: Original Papermentioning

confidence: 73%

Comparative study of Mn and Fe incorporation into GaN by metalorganic chemical vapor deposition

Kane¹,

Gupta²,

Fenwick³

et al. 2007

Physica Status Solidi (a)

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Wide bandgap diluted magnetic semiconductors (DMS) have been of interest recently due to theoretical predictions of room temperature ferromagnetism in these materials. However, the mechanism of the observed ferromagnetism of the nitrde-based DMS is still controversial, and may originate from a carriermediated, defect-related or nanoscale clustering mechanism. In this work, we present a comparative study of the incorporation of various transition metals and their effect on the optical, structural, and magnetic properties of GaN. Metal-organic chemical vapor deposition (MOCVD) has been employed to produce epitaxial films of varying thickness and manganese and iron concentrations using bis-cyclopentyldienyl (magnanese, iron) as the transition metal sources. High-resolution X-ray diffraction reveals no macroscopic secondary phases under optimized growth conditions. Magnetic hysteresis is observed at room temperature in both Ga 1-x Mn x N and Ga 1-x Fe x N, though the strength of the magnetic ordering is roughly an order of magnitude weaker in the Fe-alloyed samples. Increasing Mn concentrations significantly affects the long-range lattice ordering, and the observation of local vibrational modes (LVMs) supports the formation of nitrogen vacancies, even under optimized MOCVD growth conditions. Such vacancies form shallow donor complexes and thus contribute to self-compensation. Disorder-induced modes at 300 cm -1 and 710 cm -1 and a LVM due to vacancies at 669 cm -1 were revealed by Raman spectroscopy. The irondoped samples also show the disorder-induced modes, but the vacancy-related mode is not observed which is attributed to Fermi level and defect formation energy considerations.

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Section: Original Papermentioning

confidence: 73%

Comparative study of Mn and Fe incorporation into GaN by metalorganic chemical vapor deposition

Kane¹,

Gupta²,

Fenwick³

et al. 2007

Physica Status Solidi (a)

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“…A detailed description of the magnetization behavior is given elsewhere but will referenced as needed [46][47][48]. In general, RT ferromagnetism scaled with the Mn concentration.…”

Section: Optical Propertiesmentioning

confidence: 99%

Multifunctional III-nitride dilute magnetic semiconductor epilayers and nanostructures as a future platform for spintronic devices

et al. 2005

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This work focuses on the development of materials and growth techniques suitable for future spintronic device applications. Metal-organic chemical vapor deposition (MOCVD) was used to grow high-quality epitaxial films of varying thickness and manganese doping levels by introducing bis-cyclopentadienyl as the manganese source. Highresolution X-ray diffraction indicates that no macroscopic second phases are formed during growth, and Mn containing films are similar in crystalline quality to undoped films Atomic force microscopy revealed a 2-dimensional MOCVD step-flow growth pattern in the Mn-incorporated samples. The mean surface roughnesses of optimally grown Ga 1-x Mn x N films were almost identical to that from the as-grown template layers, with no change in growth mechanism or morphology. Various annealing steps were applied to some of the samples to reduce compensating defects and to investigate the effects of post processing on the structural, magnetic and opto-electronic properties. SQUID measurements showed an apparent ferromagnetic hysteresis behavior which persisted to room temperature. An optical absorption band around 1.5 eV was observed via transmission studies. This band is assigned to the internal Mn 3+ transition between the 5 E and the partially filled 5 T 2 levels of the 5 D state. The broadening of the absorption band is introduced by the high Mn concentration. Recharging of the Mn 3+ to Mn 2+ was found to effectively suppress these transitions resulting in a reduction of the magnetization. The structural quality, and the presence of Mn 2+ ions were confirmed by EPR spectroscopy, meanwhile no Mn-Mn interactions indicative of clustering were observed. The absence of doping-induced strain in Ga 1-x Mn x N was observed by Raman spectroscopy.

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Impact of Manganese incorporation on the structural and magnetic properties of MOCVD-grown Ga_1−xMn_xN

Cited by 2 publications

References 14 publications

Comparative study of Mn and Fe incorporation into GaN by metalorganic chemical vapor deposition

Comparative study of Mn and Fe incorporation into GaN by metalorganic chemical vapor deposition

Multifunctional III-nitride dilute magnetic semiconductor epilayers and nanostructures as a future platform for spintronic devices

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