Structural analysis of an InGaN/GaN based light emitting diode by X-ray diffraction

Öztürk, Mustafa Kemal; Yu, Haiming; Sarıkavak, B.; Korçak, Sabit; Özçelik, Süleyman; Özbay, Ekmel

doi:10.1007/s10854-009-9891-6

Cited by 20 publications

(7 citation statements)

References 20 publications

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“…All types of TDs are correlated with CLs, tilt angle and twist angle. As reported by Metzger et al [8], for (0002)-oriented GaN epitaxial films, the mean twist angle is monotonically related to the edge-type TDD with a Burgers vector of b = 1/3 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) while the mean tilt angle is monotonically related to, and can be converted into, screw type TDD with a Burgers vector of b = \0001[ [7]. Also, edge type TDs with a Burgers vector of b = 1/3 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) can reconcile an azimuthally rotation of crystallites around the normal of the surface.…”

Section: Resultsmentioning

confidence: 70%

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

Baş

Demirel²,

Akin

et al. 2014

J Mater Sci: Mater Electron

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Cataloged from PDF version of article.In this paper, we study structural and morphological properties of metal-organic chemical vapour deposition-grown InGaN/GaN light emitting diode (LED) structures with different indium (In) content by means of high-resolution X-ray diffraction, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and current-voltage characteristic (I-V). We have found out that the tilt and twist angles, lateral and vertical coherence lengths of mosaic blocks, grain size, screw and edge dislocation densities of GaN and InGaN layers, and surface roughness monotonically vary with In content. Mosaic defects obtained due to temperature using reciprocal lattice space map has revealed optimized growth temperature for active InGaN layer of MQW LED. It has been observed in this growth temperature that according to AFM result, LED structure has high crystal dimension, and is rough whereas according to PL and FTIR results, bandgap energy shifted to blue, and energy peak half-width decreased at high values. According to I-V measurements, it was observed that LED reacted against light at optimized temperature. In conclusion, we have seen that InGaN MQW structure's structural, optical and electrical results supported one another

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Section: Resultsmentioning

confidence: 70%

“…Nitrided materials, though they grow as crystallized, have often bear mosaic structure defects. These are defects such as dots, lines and volumetric defects caused by formation of In droplets, tensions arising out of rapid cooling of Al layers, lattice mismatch among layers and impurities [7].…”

Section: Resultsmentioning

confidence: 99%

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

Baş

Demirel²,

Akin

et al. 2014

J Mater Sci: Mater Electron

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“…For S.C on the left of top GaN peak InGaN peak is approximately clear but as in S.A it is also not fully distorted. These undistorted InGaN peaks can be attributed to microstructural defects [10,11]. According to Vegard's law In content(x) can be calculated by the following formula:…”

Section: Xrd Analysismentioning

confidence: 99%

Investigation of structural, optical and morphological properties of InGaN/GaN structure

et al. 2018

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In this study, InGaN/GaN structure is investigated in the temperature range of 300-500 °C with steps of 50 °C. InGaN/ GaN multi-quantum well structure is deposited on c-orientated sapphire wafer by metal organic chemical vapour deposition method. All the parameters except for temperature kept constant during growth period. InGaN/GaN structures with different In content are investigated by XRD technique. Their structural, optical and morphological characteristics are determined by high resolution X-ray diffraction, Fourier transform spectroscopy (FTIR), photo luminescence (PL), transmission and atomic force microscopy (AFM). According to FTIR and PL spectra's, it is noticed that band gap values coincide with blue region in the electromagnetic spectrum. As a result of transmission measurements it is seen that light is completely absorbed by the sample at approximately 390 nm. Using XRD technique, dislocation densities and strain are calculated. Full width at half maximum of the XRD peak values gained from X-ray diffraction are used in an alternative method called Williamson-Hall (W-H). Using W-H method, lateral and vertical crystal lengths and tilt angles are determined. Surface roughness parameters are investigated by AFM. Different properties of GaN and InGaN layers are compared as dependent on increasing temperature. According to AFM images it is seen that these structures have high surface roughness and large crystal size. All the results yielded from the mentioned methods are in good agreement with the previous works done by different authors.

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“…The peak of the InGaN layer on the left side of the GaN peak is partially separated while the peak of the AlGaN layer on the right side is more distinct and separated in sample C. The more pronounced dissociation of the InGaN peak for sample B is due to the increase of the In ratio in the composition, while the more pronounced dissociation of the AlGaN peak in sample C is attributed to the higher Al content in the composition than the sample B [7]. This is related to microstructural imperfections in the complete dissociation of these HR-XRD peaks of the InGaN and AlGaN layers [8][9][10][11][12][13][14].…”

Section: Resultsmentioning

confidence: 94%

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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Structural analysis of an InGaN/GaN based light emitting diode by X-ray diffraction

Cited by 20 publications

References 20 publications

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

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

Investigation of structural, optical and morphological properties of InGaN/GaN structure

Crystal Size and Stress Account in Reciprocal Space Map

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