Microstructural defect properties of InGaN/GaN blue light emitting diode structures

Baş, Yunus; Demirel, Pakize; Akin, Nihan; Başköse, Ceren; Özen, Yunus; Kınacı, Barış; Öztürk, Mustafa Kemal; Özçelik, Süleyman; Özbay, Ekmel

doi:10.1007/s10854-014-2108-7

Cited by 13 publications

(10 citation statements)

References 26 publications

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“…The our study of the mapping of the reciprocal space of (004) and (106) planes of the samples is given in detail. [7] in our study, the AlGaN peak, which is not fully separated to the right of the GaN peak, appears to the right of the GaN peak in Figure 3-a. The InGaN peak appears clearly visible and more understandable on the left side of the GaN peak.…”

Section: Resultscontrasting

confidence: 63%

“…The presence of the peaks of the GaN, InGaN and AlGaN layers can be more clearly understood by this mapping. For comparison, the classical HR-XRD pattern for the symmetrical plane of sample B (004) is given in Figure1 in our study [7] and the reciprocal space pattern for the same shot is given in Figure 3-a. In our study, unlike the other study, the stress study was performed with the William Hall method.…”

Section: Resultsmentioning

confidence: 99%

“…Here, λ is the wavelength of the X-ray source, Δθ is the satellite peak separation, and θ is the Bragg angle of the plane. A, B and C samples of quantum well thickness are 13.87 nm, 12.58 nm and 10.39 nm, respectively [7]. The quantum well thickness relates to the thickness of GaN and InGaN layers.…”

Section: Resultsmentioning

confidence: 99%

“…InGaN / GaN LED structure were grown by MOCVD on c-oriented (00.1) Al2O3 substrate and given in the Figure 1. The same LED samples were used for stress measurements in our study [7], Here, the growth steps are briefly mentioned. Before the epitaxial growth process was started, the Al2O3 substrate was heat treated at 1100 o C for 10 minutes in a nitrogen atmosphere to remove the oxides from the surface.…”

Section: Experimental Conditionsmentioning

confidence: 99%

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Crystal Size and Stress Account in Reciprocal Space Map

Durukan¹,

Öztürk²,

Özçelik³

et al. 2018

Journal of Polytechnic

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In this study, five periodic InGaN / GaN LED (light emitting diode) structures grown by the Metal Organic Vapor Deposition (MOCVD) at different active layer growth temperatures were studied. These structures were grown as InGaN / GaN multiple quantum wells (MQW) between c-oriented sapphire substrate and n-GaN and p-AlGaN + GaN contacts. These constructions were characterized by the high-resolution X-ray diffraction (HR-XRD) system. HRXRD patterns obtained by X-ray diffraction and Reciprocal space maps were performed from the same data. One of the most effective ways of studying the crystal lattice is reciprocal space mapping with HR-XRD technique. This technique does not damage the sample. Information can be obtained from the internal system of the sample or from the intermediate layer including substrate. Using the FWHM (βhkl) values and the elastic coefficients of the structures obtained for each of the three samples separately with the inverse mesh technique, D (nm) particle size, σ (GPa) uniform stress, ε strain, u (kJm-3) anisotropic energy density parameters were calculated. These calculations were done in a Scherrer method and Uniform Deformation Model (UDM) which is the Williamson Hall method, modified uniform Williamson stresses model (USDM) and Uniform Deformation Energy Density Model (UDEDM). The results show that the stretching in the crystal size is very little. Line expansion in HR-XRD is due to small crystal size and lattice strain. UDEDM, one of the W-H methods, has emerged as the most suitable model for stretching..

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Section: Resultscontrasting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Experimental Conditionsmentioning

confidence: 99%

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Crystal Size and Stress Account in Reciprocal Space Map

Durukan¹,

Öztürk²,

Özçelik³

et al. 2018

Journal of Polytechnic

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“…At x = 0.5 and 0.7, the diffraction angle is obtained at 2θ of 38 • with the cubic structure that matched with ref [23]. No extra peaks were observed in all samples and it may mean that no In droplets or phase separation was observed from the In x Ga 1−x N layers [24]. This indicates a good structure quality and orientation.…”

Section: Preparation Of Bulk Buffer Gan Alloysupporting

confidence: 69%

Synthesis of Nanostructure InxGa1−xN Bulk Alloys and Thin Films for LED Devices

et al. 2019

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In this study, we investigated an innovative method for the fabrication of nanostructure bulk alloys and thin films of indium gallium nitride (InxGa1-xN) as active, thin films for light-emitting diode (LED) devices using both crystal growth and thermal vacuum evaporation techniques, respectively. These methods resulted in some tangible improvements upon the usual techniques of InxGa1-xN systems. A cheap glass substrate was used for the fabrication of the LED devices instead of sapphire. Indium (In) and Gallium (Ga) metals, and ammonia (NH3) were the precursors for the alloy formation. The alloys were prepared at different growth temperatures with compositions ranging from 0.1≤x≤0.9. InxGa1-xN alloys at 0.1≤x≤0.9 had different crystallinities with respect to X-Ray diffraction (XRD) patterns where the energy bandgap that was measured by photoluminescence (PL) fell in the range between 1.3 and 2.5 eV. The bulk alloys were utilized to deposit the thin films onto the glass substrate using thermal vacuum evaporation (TVE). The XRD thin films that were prepared by TVE showed high crystallinity of cubic and hexagonal structures with high homogeneity. Using TVE, the InxGa1-xN phase separation of 0.1≤x≤0.9 was eliminated and highly detected by XRD and FESEM. Also, the Raman spectroscopy confirmed the structure that was detected by XRD. The FESEM showed a variance in the grain size of both alloys and thin films. The InxGa1-xN LED device with the structure of glass/GaN/n-In0.1Ga0.9N:n/In0.1Ga0.9N/p-In0.1Ga0.9N:Mg was checked by the light emitted by electroluminescence (EL). White light generation is a promising new direction for the fabrication of such devices based on InxGa1-xN LED devices with simple and low-cost techniques.

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On the elastic properties of INGAN/GAN LED structures

et al. 2019

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In this study, three InGaN/GaN light-emitting diode (LED) structures with five periods are investigated grown by metal organic chemical vapor deposition (MOCVD) technique. During growth of these three samples, active layer growth temperatures are adjusted as 650, 667 and 700 °C. These structures are grown on sapphire (Al 2 O 3 ) wafer as InGaN/GaN multiquantum wells (MQWs) between n-GaN and p-AlGaN + GaN contact layers. During growth, pressure and flux ratio of all sources are kept constant for all samples. Only temperature of InGaN active layer is changed. These structures are analyzed with high-resolution X-ray diffraction (HR-XRD) technique. Their surface morphologies are investigated with atomic force microscopy (AFM). Reciprocal space mapping (RSM) is made different from classical HR-XRD analyses. Using this method, mixed peaks belonging to InGaN, AlGaN and GaN layers are seen more clearly and their full width at half maximum (FWHM) values is determined with better accuracy. With FWHM gained from RSM and Williamson-Hall (W-H) method based on universal elastic coefficients of the material, particle size D (nm), uniform stress σ (GPa), strain ε and anisotropic energy density u (kJ m −3 ) parameters for the samples are calculated. The results are compared with literature. On the other hand, to have an idea about the accuracy of the results AFM images are examined. Parameters calculated showed differences but it is seen that the largest particle size is gained for GaN and the smallest is gained for AlGaN. For all parameters, it is seen that they increase for GaN layer and decrease for AlGaN layer with increasing temperature. For InGaN layer parameters, they showed both increasing and decreasing or decreasing and increasing behavior harmonically with an increase in temperature. Results showed that they are compatible with literature. Results gained from Scherrer and W-H are very near to each other.

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Microstructural defect properties of InGaN/GaN blue light emitting diode structures

Cited by 13 publications

References 26 publications

Crystal Size and Stress Account in Reciprocal Space Map

Crystal Size and Stress Account in Reciprocal Space Map

Synthesis of Nanostructure InxGa1−xN Bulk Alloys and Thin Films for LED Devices

On the elastic properties of INGAN/GAN LED structures

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