Ferromagnetism in lightly Gd doped GaN: The role of defects

2011 ◽  
Vol 1290 ◽  
Author(s):  
J. K. Mishra ◽  
S. Dhar ◽  
M. A. Khaderabad ◽  
O. Brandt
Keyword(s):  
Magnetic Properties ◽  
Molecular Beam Epitaxy ◽  
Saturation Magnetization ◽  
Magnetic Moment ◽  
Molecular Beam ◽  
Defect Density ◽  
Defect Cluster ◽  
Clear Correlation ◽  
Defect Band

ABSTRACTGd:GaN layers grown with different Gd concentrations by molecular beam epitaxy (MBE) are studied using photoconductivity and photo-thermoelectric power spectroscopy. Our study reveals that the incorporation of Gd produces a large concentration of acceptor-like defects in the GaN lattice. The defect band is found to be located ~450meV above the valence band. Moreover, the concentration of defects is found to increase with the Gd concentration. The effect of annealing on the structural and the magnetic properties of GaN implanted with Gd is also investigated. A clear correlation between the saturation magnetization and the defect density is observed in implanted samples. The colossal magnetic moment per Gd ion and the ferromagnetism observed in this material is explained in terms of the formation of giant defect cluster around each Gd ion.

ROLE OF DEFECTS IN SHAPING THE MAGNETIC PROPERTIES OF Gd-DOPED GaN

2011 ◽  
Vol 10 (04n05) ◽  
pp. 555-558 ◽  
Author(s):  
J. K. MISHRA ◽  
S. DHAR ◽  
M. A. KHADERABAD
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Magnetic Moment ◽  
Defect Density ◽  
Wavelength Dependence ◽  
Defect Cluster ◽  
Clear Correlation

The effect of annealing on the structural and the magnetic properties of GaN implanted with Gd is investigated. The wavelength dependence of the photoconductivity of Gd:GaN layers doped in situ is also studied. These results show that Gd incorporation produces defects not only in implanted samples, but also in Gd:GaN layers doped in situ. A clear correlation between the saturation magnetization and the defect density is observed in implanted samples. A model has been proposed to explain the effects of colossal magnetic moment per Gd ion and associated ferromagnetism observed in this system in terms of the formation of giant defect cluster around each Gd ion.

Role of growth conditions on magnetic properties of AlCrN grown by molecular beam epitaxy

2005 ◽  
Vol 86 (5) ◽  
pp. 052101 ◽  
Author(s):  
R. M. Frazier ◽  
G. T. Thaler ◽  
J. Y. Leifer ◽  
J. K. Hite ◽  
B. P. Gila ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

scholarly journals Role of Stronger Interlayer van der Waals Coupling in Twin‐Free Molecular Beam Epitaxy of 2D Chalcogenides

2021 ◽  
pp. 2100438
Author(s):  
Wouter Mortelmans ◽  
Karel De Smet ◽  
Ruishen Meng ◽  
Michel Houssa ◽  
Stefan De Gendt ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Van Der Waals

Correlation between the violet luminescence intensity and defect density in AlN epilayers grown by ammonia-source molecular beam epitaxy

2008 ◽  
Vol 5 (6) ◽  
pp. 2129-2132 ◽  
Author(s):  
Takuya Hoshi ◽  
Takahiro Koyama ◽  
Mariko Sugawara ◽  
Akira Uedono ◽  
John F. Kaeding ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Luminescence Intensity ◽  
Molecular Beam ◽  
Defect Density ◽  
Violet Luminescence ◽  
Ammonia Source

Role of Surface Reconstruction and External Ion Beam in the Growth Kinetics of III-V Molecular Beam Epitaxy

1987 ◽  
Vol 94 ◽  
Author(s):  
S. B. Ogale ◽  
M. Thomsen ◽  
A. Madhukar
Keyword(s):  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Surface Reconstruction ◽  
Molecular Beam ◽  
Ion Beam ◽  
Growth Front ◽  
Kinetic Rates ◽  
Kinetics Of ◽  
Low Temperature Epitaxy

ABSTRACTComputer simulations of III-V molecular beam epitaxy (MBE) show that surface reconstruction induced modulation of kinetic rates could give rise to ordering in alloys. Results are also presented for the possible influence of an external ion beam in achieving low temperature epitaxy as well as smoother growth front under usual conditions.

Contamination in molecular beam epitaxy: the role of arsenic drag effect

1997 ◽  
Vol 175-176 ◽  
pp. 1270-1277 ◽  
Author(s):  
Z.R. Wasilewski ◽  
S.J. Rolfe ◽  
R.A. Wilson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Drag Effect

Study of nitrogen incorporation into GaInNAs: The role of growth temperature in molecular beam epitaxy

2012 ◽  
Vol 112 (2) ◽  
pp. 023504 ◽  
Author(s):  
V.-M. Korpijärvi ◽  
A. Aho ◽  
P. Laukkanen ◽  
A. Tukiainen ◽  
A. Laakso ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Growth Temperature ◽  
Molecular Beam ◽  
Nitrogen Incorporation

Homo- and Hetero-Epitaxial Gallium Nitride Grown by Molecular Beam Epitaxy

1998 ◽  
Vol 537 ◽  
Author(s):  
C.T. Foxon ◽  
T.S. Cheng ◽  
D. Korakakis ◽  
S.V. Novikov ◽  
R.P. Campion ◽  
...  
Keyword(s):  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
Boundary Structure ◽  
Quantum Well Structures ◽  
Flat Surfaces ◽  
Grain Boundary Structure ◽  
Bulk Gan ◽  
Atomically Flat

AbstractVarious methods have been used to initiate growth by Molecular Beam Epitaxy (MBE) of GaN on sapphire, or other substrates, but there is always a problem with morphology and with a high defect density which results in the formation of a sub-grain boundary structure. We show that by using, homo-epitaxial growth on properly prepared bulk GaN substrates, combined with high temperature growth, we obtain a significant improvement in surface morphology. Growth at sufficiently high temperature leads to a rapid smoothing of the surface and to almost atomically flat surfaces over relatively large areas. Multi-Quantum Well structures grown on such GaN epitaxial films are dislocation free with abrupt interfaces.

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