Photoluminescence Study of Plastically Deformed GaN

ABSTRACTWe report the photoluminescence characteristics of fresh dislocations introduced by the plastic deformation in GaN bulk crystals. GaN crystals prepared from free standing wafers grown by the HVPE technique were compressed plastically at 900 to 1000°C. In the deformed crystals (a/3) (1120) dislocations on the (1110) prismatic plane, corresponding to the so-called threading dislocations, were observed in TEM. In the PL studies at 11K the intensity of the near band-edge luminescence decreased drastically in the deformed GaN by about 1/12 than that of the as-grown GaN, which seems to imply the introduction of a high density of non-radiative reco!m bination centers into GaN! during the plastic deformation. By the plastic deformation the yellow band luminescence decreased remarkably meanwhile the red band and other new luminescence developed relatively. It is found that dislocations do not originate to the yellow luminescence but the red luminescence.

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Properties of Free-Standing GaN Bulk Crystals Grown by HVPE

MRS Proceedings ◽

10.1557/proc-482-269 ◽

1997 ◽

Vol 482 ◽

Cited By ~ 27

Author(s):

YU. Melnik ◽

A. Nikolaev ◽

I. Nikitina ◽

K. Vassilevski ◽

V. Dmitriev

Keyword(s):

Hydride Vapor Phase Epitaxy ◽

Bulk Crystals ◽

Free Standing ◽

Yellow Band ◽

Rocking Curve ◽

X Ray ◽

Lattice Constants ◽

Interface Surface ◽

Peak Intensity ◽

Residual Strains

AbstractGaN wafers 200 μm thick and 30 mm diameter were fabricated. GaN was grown by hydride vapor phase epitaxy on SiC substrates and removed from the substrate by reactive ion etching. Lateral size of the GaN wafers was equal to the size of the initial SiC substrates. GaN wafers were cleaved in pieces and these pieces were characterised. It was found that after the fabrication, GaN crystals were slightly deformed and strained. An anneal at 830°C in nitrogen ambient eliminated the residual strains. The FWHM of ω-scan (0002) x-ray rocking curve for annealed crystals was less than 140 arcsec for both sides of the best GaN crystals. The lattice constants measured from both sides of the crystals were c =5.1853±0.0003 Å and a = 3.1889±0.0001 Å. The Nd – Na concentration determined by a mercury probe was about 2×1017cm−3 for as-grown GaN surface and about 2×1019cm−3 for former interface surface. Photoluminescence spectrum taken at 17 K revealed an edge peak at 3.472 eV with the FWHM value of 2.3 meV. A ratio of the edge peak intensity to the intensity of yellow band was higher than 1000. Initial TEM experiments were performed.

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Propagation of threading dislocations and effects of Burgers vectors in HVPE-grown GaN bulk crystals on Na-flux-grown GaN substrates

Journal of Applied Physics ◽

10.1063/5.0053766 ◽

2021 ◽

Vol 129 (22) ◽

pp. 225701

Author(s):

T. Hamachi ◽

T. Tohei ◽

Y. Hayashi ◽

M. Imanishi ◽

S. Usami ◽

...

Keyword(s):

Threading Dislocations ◽

Bulk Crystals

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The Elastic Moduli of Silver Thin Films Measured with a New Microtensile Tester

MRS Proceedings ◽

10.1557/proc-239-239 ◽

1991 ◽

Vol 239 ◽

Cited By ~ 1

Author(s):

J. Ruud ◽

D. Josell ◽

A. L. Greer ◽

F. Spaepen

Keyword(s):

Thin Film ◽

Thin Films ◽

Diffraction Grating ◽

Strain Measurement ◽

Elastic Moduli ◽

Two Dimensional ◽

Bulk Crystals ◽

Free Standing ◽

Tensile Direction ◽

Silver Thin Films

ABSTRACTA new design for a thin film microtensile tester is presented. The strain is measured directly on the free-standing thin film from the displacement of laser spots diffracted from a thin grating applied to its surface by photolithography. The diffraction grating is two-dimensional, allowing strain measurement both along and transverse to the tensile direction. In principle, both Young's modulus and Poisson's ratio of a thin film can be determined. Ag thin films with strong <111> texture were tested. The measured Young moduli agreed with those measured on bulk crystals, but the measured Poisson ratios were low, most likely due to slight transverse folding of the film that developed during the test.

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Photoluminescence Excitation Spectroscopy of Carbon-Doped Gallium Nitride

MRS Proceedings ◽

10.1557/proc-537-g3.67 ◽

1998 ◽

Vol 537 ◽

Author(s):

E. E. Reuter ◽

R. Zhang ◽

T. F. Kuech ◽

S. G. Bishop

Keyword(s):

Complete Characterization ◽

Photoluminescence Excitation ◽

Yellow Luminescence ◽

Broad Excitation Band ◽

Carbon Doped ◽

Sapphire Substrates ◽

Red Luminescence ◽

Unusual Shape

AbstractWe have done a comparative study of carbon-doped GaN and undoped GaN utilizing photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies in order to investigate deep levels involved in yellow luminescence (YL) and red luminescence (RL). When the GaN was excited by above-bandgap light, red luminescence (RL) centered at 1.82 eV was the dominant below-gap PL from undoped GaN, but carbon-doped GaN below-gap PL was dominated by yellow luminescence (YL) centered at 2.2 eV. When exciting PL below the band-gap with 2.4 eV light, undoped GaN had a RL peak centered at 1.5 eV and carbon-doped GaN had a RL peak centered at 1.65 eV. PLE spectra of carbon-doped GaN, detecting at 1.56 eV, exhibited a strong, broad excitation band extending from about 2.1 to 2.8 eV with an unusual shape that may be due to two or more overlapping excitation bands. This RL PLE band was not observed in undoped GaN. We also demonstrate that PL spectra excited by below gap light in GaN films on sapphire substrates are readily contaminated by 1.6-1.8 eV and 2.1-2.5 eV chromium-related emission from the substrate. A complete characterization of the Cr emission and excitation bands for sapphire substrates enables the determination of the excitation and detection wavelengths required to obtain GaN PL and PLE spectra that are free of contributions from substrate emission.

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ChemInform Abstract: NEAR BAND-EDGE LUMINESCENCE IN ZINC SELENIDE GROWN FROM GALLIUM SOLUTION

Chemischer Informationsdienst ◽

10.1002/chin.197921006 ◽

1979 ◽

Vol 10 (21) ◽

Author(s):

B. J. FITZPATRICK ◽

R. N. BHARGAVA ◽

S. P. HERKO ◽

P. M. HARNACK

Keyword(s):

Zinc Selenide ◽

Band Edge ◽

Near Band Edge ◽

Edge Luminescence ◽

Band Edge Luminescence

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The influence of temperature on plastic deformation of free standing thin Al–Zn–Mg–Cu films

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2003.10.080 ◽

2004 ◽

Vol 378 (1-2) ◽

pp. 312-315 ◽

Cited By ~ 2

Author(s):

M. Cieslar ◽

V. Oliva ◽

A. Karimi ◽

J.-L. Martin

Keyword(s):

Plastic Deformation ◽

Free Standing ◽

Influence Of Temperature ◽

Cu Films ◽

Influence Of Temperature On

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Identification of Burgers vectors of threading dislocations in free-standing GaN substrates via multiphoton-excitation photoluminescence mapping

Applied Physics Express ◽

10.35848/1882-0786/abf31b ◽

2021 ◽

Author(s):

Mayuko Tsukakoshi ◽

Tomoyuki TANIKAWA ◽

Takumi Yamada ◽

Masayuki Imanishi ◽

Yusuke MORI ◽

...

Keyword(s):

Threading Dislocations ◽

Multiphoton Excitation ◽

Free Standing

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Yellow luminescence in Mg-doped GaN

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s109257830000154x ◽

1997 ◽

Vol 2 ◽

Cited By ~ 8

Author(s):

F. J. Sánchez ◽

F. Calle ◽

D. Basak ◽

J. M. G. Tijero ◽

M. A. Sánchez-García ◽

...

Keyword(s):

Valence Band ◽

Yellow Emission ◽

Yellow Luminescence ◽

Excitation Energies ◽

Yellow Band ◽

Mg Doping ◽

Mg Doped

Optical thresholds, that correspond to a level located at 1 eV above the valence band, are observed by photocapacitance techniques in n-type Mg-doped GaN. In undoped GaN, this level has been previously related to the yellow emission detected by photoluminescence. In Mg-doped GaN, this yellow luminescence is only observed for excitation energies below the Mg-related band (2.9 - 3 eV). This result evidences that Mg-doping may reduce but not avoid the formation of the yellow band related defects in n-type and semiinsulating Mg-doped samples. The fact that the yellow luminescence is not observed for excitation energies above the bandgap may be justified by a higher efficiency of the Mg-related recombination path.

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