The Fabrication of Ag Islands on AlN/GaN/AlN/Si(111) by Using Thermal Evaporator and Thermal Annealing Methods

2011 ◽  
Vol 364 ◽  
pp. 327-332 ◽  
Author(s):  
Mohd Zaki Mohd Yusoff ◽  
А. Mahyuddin ◽  
Hassan Zainuriah ◽  
Abu Hassan Haslan ◽  
Mat Johar Abdullah ◽  
...  
Keyword(s):  
Yellow Emission ◽  
Band Edge Emission ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
Treated Sample ◽  
Thermal Evaporator ◽  
Yellow Emission Band

In this paper, we studied growth of AlN/GaN/AlN on Si (111) by using plasma assisted molecular beam epitaxy (PA-MBE) system. The structural and optical characteristics of the sample have been investigated by using high resolution X-ray diffraction (HR-XRD), Raman spectroscopy and photoluminescence (PL). PL spectrum of the sample has shown sharp and intense band edge emission of GaN with the absence of yellow emission band, indicating good crystal quality of the sample. The silver (Ag) metal contact was then deposited on the sample followed by thermal treatment at 500°C and 700°C, respectively. Treated sample at 700°C showed good spherical Ag islands on sample compared to the treated sample at 500°C. The effect of Ag islands on the electrical characteristics of sample was also examined by usingI-Vmeasurement. The results showed that the treated sample at 700°C has decreased the photo-current of Schottky diode.

scholarly journals Growth and Characterization of BxGa1−xN on 6H-SiC (0001) by Movpe

1999 ◽  
Vol 4 (S1) ◽  
pp. 429-434 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  
Keyword(s):  
Single Phase ◽  
Band Edge Emission ◽  
Reactant Ratio ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Edge Emission ◽  
X Ray ◽  
Two Phases

Boron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGa1−xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGa1−xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGa1−xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGa1−xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.

Growth and Characterization of BxGal-xN on 6H-SiC (0001) by MOVPE

1998 ◽  
Vol 537 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  
Keyword(s):  
Single Phase ◽  
Band Edge Emission ◽  
Reactant Ratio ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Edge Emission ◽  
X Ray ◽  
Two Phases

AbstractBoron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGal-xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGal-xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGal-xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGal-xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.

Al2O3 as a Transition Layer for GaN and InGaN Growth on ZnO by MOCVD

2009 ◽  
Vol 1201 ◽  
Author(s):  
Nola Li ◽  
Shen-Jie Wang ◽  
William E. Fenwick ◽  
Andrew Melton ◽  
Chung-Lung Huang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Vapor ◽  
Shallow Donor ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
20 Nm ◽  
Related Level

AbstractGaN and InGaN layers were grown on annealed 20 and 50nm Al2O3/ZnO substrates by metalorganic chemical vapor deposition (MOCVD). GaN was only observed by high resolution x-ray diffraction (HRXRD) on 20 nm Al2O3/ZnO substrates. Room temperature photoluminescence (RT-PL) showed the red shift of the GaN near band-edge emission, which might be from oxygen incorporation forming a shallow donor-related level in GaN. HRXRD measurements revealed that (0002) InGaN layers were also successfully grown on 20nm Al2O3/ZnO substrates. In addition, thick InGaN layers (∼200-300nm) were successfully grown on Al2O3/ZnO and bare ZnO substrates. These results are significant as previous studies showed decomposition of the layer at InGaN thicknesses of 100nm or less.

Pendeo-Epitaxial Growth of GaN on SiC and Silicon Substrates via Metalorganic Chemical Vapor Deposition

1999 ◽  
Vol 572 ◽  
Author(s):  
K. J. Linthicum ◽  
T. Gehrke ◽  
D. Thomson ◽  
C. Ronning ◽  
E. P. Carlson ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Silicon Substrates ◽  
Lateral Growth ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
Si Substrates ◽  
Crystallographic Tilt

ABSTRACTPendeo-epitaxial lateral growth (PE) of GaN epilayers on (0001) 6H-silicon carbide and (011) Si substrates has been achieved. Growth on the latter substrate was accomplished through the use of a 3C-SiC transition layer. The coalesced PE GaN epilayers were characterized using scanning electron diffraction, x-ray diffraction and photoluminescence spectroscopy. The regions of lateral growth exhibited ∼0.2° crystallographic tilt relative to the seed layer. The GaN seed and PE epilayers grown on the 3C-SiC/Si substrates exhibited comparable optical characteristics to the GaN seed and PE grown on 6H-SiC substrates. The near band-edge emission of the GaN/3C-SiC/Si seed was 3.450 eV (FWHM ∼ 19 meV) and the GaN/6H-SiC seed was 3.466 eV (FWHM ∼ 4 meV).

scholarly journals GaN Layers Grown by HVPE on P-type 6H-SiC Substrates

1996 ◽  
Vol 1 ◽  
Author(s):  
A.E. Nikolaev ◽  
Yu.V. Melnik ◽  
M.N. Blashenkov ◽  
N.I. Kuznetsov ◽  
I.P. Nikitina ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Crystal Quality ◽  
Band Edge ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
P Type

Gallium nitride films were successfully grown by HVPE technique on p-type 6H-SiC substrate. The layers exhibit high crystal quality as was determined by X-ray diffraction. Photoluminescence (PL) of these films was measured. The PL spectra were dominated by band edge emission. Concentration Nd-Na in undoped epitaxial layers ranged from 2×1017 to 1×1019cm−3. Mesa-structures formed by reactive ion etching showed good rectifying current-voltage characteristics for GaN/SiC pn heterojunctions.

Optical Properties of Wurtzite-and Zincblende-GaN Films Grown by RF Plasma-MBE

1995 ◽  
Vol 395 ◽  
Author(s):  
F. Semendy ◽  
N. Bambha ◽  
J.G. Kim ◽  
H. Liu ◽  
R.M. Park
Keyword(s):  
Optical Properties ◽  
Molecular Beam ◽  
Plasma Discharge ◽  
Rf Plasma ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
Rf Plasma Discharge

ABSTRACTBoth wurtzite-and zincblende-GaN films have been grown on sapphire and MgO substrates, respectively, and examined by photoluminescence and x-ray analysis. GaN films were grown on suitably prepared Al2O3 and MgO substrates by molecular beam epitaxy employing a rf plasma discharge, nitrogen free radical source. The wurtzite-and zincblende-GaN films exhibited dominant near band-edge emission, the nature of which will be compared and contrasted for both phases in this paper. X-ray diffraction data for both phases will also be discussed.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Study of the quality of GaAs thin film on Si substrate by X-ray diffraction method

1990 ◽  
Vol 7 (7) ◽  
pp. 308-311
Author(s):  
Li Chaorong ◽  
Mai Zhenhong ◽  
Cui Shufan ◽  
Zhou Junming ◽  
Yutian Wang
Keyword(s):  
Thin Film ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray

scholarly journals High temperature structural study of decagonal Al-Cu-Rh quasicrystal.

2014 ◽  
Vol 70 (a1) ◽  
pp. C94-C94
Author(s):  
Pawel Kuczera ◽  
Walter Steurer
Keyword(s):  
Structural Changes ◽  
Configurational Entropy ◽  
Lattice Vibrations ◽  
X Ray Diffraction ◽  
Stabilization Mechanism ◽  
X Ray ◽  
Comparative Structure ◽  
The Stability

The structure of d(ecagonal)-Al-Cu-Rh has been studied as a function of temperature by in-situ single-crystal X-ray diffraction in order to contribute to the discussion on energy or entropy stabilization of quasicrystals (QC) [1]. The experiments were performed at 293 K, 1223 K, 1153 K, 1083 K, and 1013 K. A common subset of 1460 unique reflections was used for the comparative structure refinements at each temperature. The results obtained for the HT structure refinements of d-Al-Cu-Rh QC seem to contradict a pure phasonic-entropy-based stabilization mechanism [2] for this QC. The trends observed for the ln func(I(T1 )/I(T2 )) vs.|k⊥ |^2 plots indicate that the best on-average quasiperiodic order exists between 1083 K and 1153 K, however, what that actually means is unclear. It could indicate towards a small phasonic contribution to entropy, but such contribution is not seen in the structure refinements. A rough estimation of the hypothetic phason instability temperature shows that it would be kinetically inaccessible and thus the phase transition to a 12 Å low T structure (at ~800 K) is most likely not phason-driven. Except for the obvious increase in the amplitude of the thermal motion, no other significant structural changes, in particular no sources of additional phason-related configurational entropy, were found. All structures are refined to very similar R-values, which proves that the quality of the refinement at each temperature is the same. This suggests, that concerning the stability factors, some QCs could be similar to other HT complex intermetallic phases. The experimental results clearly show that at least the ~4 Å structure of d-Al-Cu-Rh is a HT phase therefore entropy plays an important role in its stabilisation mechanism lowering the free energy. However, the main source of this entropy is probably not related to phason flips, but rather to lattice vibrations, occupational disorder unrelated to phason flips like split positions along the periodic axis.

Crystalline and Electrical Properties of Ferroelectric Silver Niobate-tantalate thin Films

2000 ◽  
Vol 655 ◽  
Author(s):  
Jung-Hyuk Koh ◽  
S.I. Khartsev ◽  
Alex Grishin ◽  
Vladimir Petrovsky
Keyword(s):  
Temperature Stability ◽  
Frequency Dispersion ◽  
Processing Temperature ◽  
High Temperature Stability ◽  
X Ray Diffraction ◽  
Ferroelectric State ◽  
X Ray ◽  
Ferroelectric Hysteresis ◽  
First Time

AbstractFor the first time AgTa0.38Nb0.62O3 (ATN) films have been grown on the La0.7Sr0.3CoO3 (LSCO)/LaAlO3 single crystal as well as onto Pt80Ir20 (PtIr) polycrystalline substrate. Comprehensive X-ray diffraction analyses reveal epitaxial quality of ATN and LSCO films on the LaAlO3(001) substrate, while ATN/PtIr films have been found to be (001) preferentially oriented. Dielectric spectroscopy performed for ATN films and bulk ceramics in a wide temperature range 77 to 420 K shows the structural monoclinic M1-to-monoclinic M2 phase transition occurs in films at the temperature 60 °C lower than in ceramics. The tracing of the ferroelectric hysteresis P-E loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields remnant polarization of 0.4 μC/cm2 @ 77 K. Weak frequency dispersion, high temperature stability of dielectric properties as well as low processing temperature of 550 °C make ATN films to be attractive for various applications.

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