Characterization of Sub-Surface Structures by Double Crystal X-Ray Diffraction

1986 ◽  
Vol 82 ◽  
Author(s):  
D.K. Bowen ◽  
M.J. Hill ◽  
B.K. Tanner

ABSTRACTThe application of double crystal X-ray diffractometry and computer simulation to the characterization of lattice parameter variations through the thickness of heteroepitaxial layers is reviewed. The sensitivity is demonstrated in studies of graded layers grown by vapour phase epitaxy. Capping layers significantly affect rocking curves from superlattice structures. The use of glancing angle diffraction to characterize thin, low period multilayers is examined.

2000 ◽  
Vol 5 (S1) ◽  
pp. 412-424
Author(s):  
Jung Han ◽  
Jeffrey J. Figiel ◽  
Gary A. Petersen ◽  
Samuel M. Myers ◽  
Mary H. Crawford ◽  
...  

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.


1992 ◽  
Vol 7 (5) ◽  
pp. 627-631 ◽  
Author(s):  
A R Powell ◽  
D K Bowen ◽  
M Wormington ◽  
R A Kubiak ◽  
E H C Parker ◽  
...  

1999 ◽  
Vol 595 ◽  
Author(s):  
Jung Han ◽  
Jeffrey J. Figiel ◽  
Gary A. Petersen ◽  
Samuel M. Myers ◽  
Mary H. Crawford ◽  
...  

AbstractWe report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Duc V. Dinh ◽  
Nan Hu ◽  
Yoshio Honda ◽  
Hiroshi Amano ◽  
Markus Pristovsek

Abstract Growth of AlxGa1−xN layers (0 ≤ x ≤ 1) simultaneously on polar (0001), semipolar ($$10\bar{{\rm{1}}}$$ 10 1 ¯ 3) and ($$11\bar{{\rm{2}}}2$$ 11 2 ¯ 2 ), as well as nonpolar ($$10\bar{{\rm{1}}}0$$ 10 1 ¯ 0 ) and ($$11\bar{{\rm{2}}}0$$ 11 2 ¯ 0 ) AlN templates, which were grown on planar sapphire substrates, has been investigated by metal-organic vapour phase epitaxy. By taking into account anisotropic in-plane strain of semi- and non-polar layers, their aluminium incorporation has been determined by x-ray diffraction analysis. Optical emission energy of the layers was obtained from room-temperature photoluminescence spectra, and their effective bandgap energy was estimated from room-temperature pseudo-dielectric functions. Both x-ray diffraction and optical data consistently show that aluminium incorporation is comparable on the polar, semi- and non-polar planes.


1988 ◽  
Vol 32 ◽  
pp. 311-321 ◽  
Author(s):  
R.A. Larsen ◽  
T.F. McNulty ◽  
R.P. Goehner ◽  
K.R. Crystal

AbstractThe use of conventional θ/2θ diffraction methods for the characterization of polycrystalline thin films is not in general a satisfactory technique due to the relatively deep penetration of x-ray photons in most materials. Glancing incidence diffraction (GID) can compensate for the penetration problems inherent in the θ/2θ geometry. Parallel beam geometry has been developed in conjunction with GID to eliminate the focusing aberrations encountered when performing these types of measurements. During the past yearwe developed a parallel beam attachment which we have successfully configured to a number of systems.


1989 ◽  
Vol 33 ◽  
pp. 1-11 ◽  
Author(s):  
B. K. Tanner

AbstractUse of a reference crystal to condition the beam in the double-axis diffractometer permits the Bragg peak width to be reduced to the correlation of the two crystal reflecting ranges. Some recent applications of double axis diffractometry to the study of heteroepitaxial layers are discussed. The advantages of multiple reflections for beam conditioning and the four reflection DuMond monochromator are examined. Glancing incidence and exit diffractometry permits the study of very thin layers, down to a few tens of nanometres in thickness and both synchrotron radiation and skew reflections can be used to tune the glancing angle close to the critical angle. Recent applications of triple-axis diffraction, where an analyzer crystal is used after the specimen, to the study of very thin single epitaxial layers and multiquantum well structures are reviewed.


2011 ◽  
Vol 25 (07) ◽  
pp. 1013-1019 ◽  
Author(s):  
S. AZADEHRANJBAR ◽  
F. KARIMZADEH ◽  
M. H. ENAYATI

Nanocrystalline FeNi and Ni 3 Fe alloys were prepared by mechanical alloying of Fe and Ni elemental powders using a planetary ball mill under protection atmosphere. X-ray diffraction measurements were performed to follow alloy formation process in these alloys. A heat treatment of 1 h at 800°C was carried out to relax the internal stresses of the milled samples. Morphological evolution of powder particles was revealed by scanning electron microscopy. The value of lattice parameter was reached to 0.35762 nm and the hardness was found to be 686 HV at 30 h milled FeNi powder. In the case of Ni 3 Fe the values of 0.3554 nm and 720 HV were obtained for lattice parameter and hardness, respectively.


2015 ◽  
Vol 819 ◽  
pp. 198-203
Author(s):  
Nur Farahin Abdul Hamid ◽  
Rozana Aina Maulat Osman ◽  
Mohd Sobri Idris ◽  
Tze Qing Tan

La-doped barium titanate (BaTiO3) was prepared using conventional solid state synthesis route. All peaks for sample x=0 are approaching the phase pure of BaTiO3 structure with tetragonal crystal structure (P4mm). Sintering of pressed powder are performed at 1300oC, 1400oC and 1450oC for overnight for pure BaTiO3 and 1350oC for 3 days for BaTiO3 doped lanthanum with intermittent grinding. Phase transition was studied by different x composition. The changes in the crystal structure of the composition x=0.1 and 0.2 were detected by using X-ray diffraction (XRD). The phase changes between tetragonal-cubic and cubic-tetragonal depending on the temperature. Rietveld Refinement analysis is carried out to determine the lattice parameter and unit cell for BaTiO3.


2004 ◽  
Vol 51 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Sanjay K. Rai ◽  
Anish Kumar ◽  
Vani Shankar ◽  
T. Jayakumar ◽  
K. Bhanu Sankara Rao ◽  
...  

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