Nonpolar growth and characterization of a-plane InGaN/GaN quantum well structures with different indium compositions

Song, Hooyoung; Kim, Jin Soak; Kim, Eun Kyu; Lee, Sungho; Kim, Jae Bum; Son, Ji-Su; Hwang, Sungmin

doi:10.1016/j.sse.2010.05.015

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…The relative intensity of InGaN QW emission (defined as the integrated emission intensity of InGaN QWs versus the total integrated emission intensity), is nevertheless, higher at room temperature than at low temperature. This behavior, commonly observed for these types of structures, 37,38 is attributed to the thermally enhanced mobility of photo-excited carriers, which consequently reach the InGaN QWs (i.e. the lowest energy emission band) more easily.…”

Section: Preliminary Structural and Optical Characterization: Xrd And Plmentioning

confidence: 64%

Quantitative parameters for the examination of InGaN QW multilayers by low-loss EELS

Eljarrat

López‐Conesa

Magén

et al. 2016

Phys. Chem. Chem. Phys.

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We present a detailed examination of a multiple InxGa1-xN quantum well (QW) structure for optoelectronic applications. The characterization is carried out using scanning transmission electron microscopy (STEM), combining high-angle annular dark field (HAADF) imaging and electron energy loss spectroscopy (EELS). Fluctuations in the QW thickness and composition are observed in atomic resolution images. The impact of these small changes on the electronic properties of the semiconductor material is measured through spatially localized low-loss EELS, obtaining band gap and plasmon energy values. Because of the small size of the InGaN QW layers additional effects hinder the analysis. Hence, additional parameters were explored, which can be assessed using the same EELS data and give further information. For instance, plasmon width was studied using a model-based fit approach to the plasmon peak; observing a broadening of this peak can be related to the chemical and structural inhomogeneity in the InGaN QW layers. Additionally, Kramers-Kronig analysis (KKA) was used to calculate the complex dielectric function (CDF) from the EELS spectrum images (SIs). After this analysis, the electron effective mass and the sample absolute thickness were obtained, and an alternative method for the assessment of plasmon energy was demonstrated. Also after KKA, the normalization of the energy-loss spectrum allows us to analyze the Ga 3d transition, which provides additional chemical information at great spatial resolution. Each one of these methods is presented in this work together with a critical discussion of their advantages and drawbacks.

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Section: Preliminary Structural and Optical Characterization: Xrd And Plmentioning

confidence: 64%

Quantitative parameters for the examination of InGaN QW multilayers by low-loss EELS

Eljarrat

López‐Conesa

Magén

et al. 2016

Phys. Chem. Chem. Phys.

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“…importance for the field of a-plane GaN layers, in which a significant fraction of the literature mainly relies on XRD to assess the crystal quality of the layers [14][15][16][18][19][20]26,23,24,27,29]. The notable exceptions are Song et al [21], Hao et al [17], Chakraborty et al [23], Araki et al [28] and Johnston et al [25,22] with some additional AFM and XRD characterizations by Moram et al [35,32]. Defect densities derived in these detailed studies are comparable to those of obtained here.…”

Section: Resultsmentioning

confidence: 99%

“…Many of the a-plane GaN in situ defect reduction techniques are inspired by standard c-plane recipes [13]: the use of GaN lowtemperature nucleation layers (LTNLs) grown in hydrogen or nitrogen carrier gas [14][15][16][17], high-or low-temperature aluminium nitride nucleation layers [14,[18][19][20] and the deliberate delay of island coalescence via three dimensional to two dimensional growth mode transitions (3D2D) [21,22,17]. Some other techniques, also derived from c-plane recipes, are based on growth interruptions by the inclusion of interlayers: single or multiple silicon nitride ( SiN x ) interlayers [23,24,21,17] or scandium nitride interlayers [25], which can be followed by a 3D growth step [12].…”

Section: Introductionmentioning

confidence: 99%

“…Some other techniques, also derived from c-plane recipes, are based on growth interruptions by the inclusion of interlayers: single or multiple silicon nitride ( SiN x ) interlayers [23,24,21,17] or scandium nitride interlayers [25], which can be followed by a 3D growth step [12]. Lastly, novel growth techniques have been explored, such as high silicon doping [26] or epigrowth without the use of a nucleation layer, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of growth methods for the heteroepitaxy of non-polar(112¯0)GAN on sapphire by MOVPE

Oehler

Sutherland

Zhu

et al. 2014

Journal of Crystal Growth

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a b s t r a c tNon-polar a-plane gallium nitride (GaN) films have been grown on r-plane ð1102Þ sapphire by metal organic vapour phase epitaxy (MOVPE). A total of five in situ defect reduction techniques for a-plane GaN are compared, including two variants with a low temperature GaN nucleation layer (LTNL) and three variants without LTNL, in which the high-temperature growth of GaN is performed directly on the sapphire using various crystallite sizes. The material quality is investigated by photoluminescence (PL), X-ray diffraction, cathodoluminescence, atomic force and optical microscopy. It is found that all layers are anisotropically strained with threading dislocation densities over 10 9 cm À 2 . The PL spectrum is typically dominated by emission from basal plane stacking faults. Overall, growth techniques without LTNL do not yield any particular improvement and even result in the creation of new defects, i.e. inversion domains, which are seldom observed if a low temperature GaN nucleation layer is used. The best growth method uses a LTNL combined with a single silicon nitride interlayer.

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Organic Step Edge Driven Heteroquasiepitaxial Growth of Organic Multilayer Films

Chen

Lunt

2016

Adv Materials Inter

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bottom-up exploiting a new non-surface energy driven mechanism. Each layer is shown to grow with a well-defi ned quasiepitaxial registry regardless of the incommensurate unit cells, where the multilayer pair growth is maintained for multiple cycles. While there is a close surface energy matching between the LES of DIP and NTCDA, it is a non-lowest energy plane of DIP that is formed in the multilayer structure. While surface energy matching of the lowest energy surface is likely to play an important role in many other organic-organic systems, the ability to grow this multilayer system with sustained ordering provides an intriguing new mechanism in organic-organic quasiepitaxy. A combination of in situ real time diffraction techniques, energy landscape calculations, and sub-monolayer microscopy on the initial growth reveals that the molecular orientation is driven by step edge driven nucleation instead of surface energy potentials of the intraterrace landscape. This case of organic step edge driven growth stems from a different mechanism than that for atomic step edge growth [24][25][26] due to the additional degrees of molecular freedom and molecular bonding. The ability to grow epitaxial superlattice structures has had signifi cant importance in inorganic quantum wells and quantum dots applications, such as with photodetectors, light emitting diodes, and solid state laser diodes. [27][28][29][30][31][32][33] The organic equivalent could have similarly substantial impact but has not been widely accessible previously. Thus, this new growth mode for achieving quasiepitaxial multilayers could provide novel pathways to fabricate highly ordered organic superlattices with tunable orientation for enhanced excitonic electronic devices.We start with NTCDA, a wide bandgap semiconductor, which we have already demonstrated to grow quasiepitaxially on KBr crystals with excellent ordering and well-defi ned registry at room temperature. [ 23 ] The archetypal perylene derivation, DIP, was paired with NTCDA due to its (1) promising electron and hole mobilities in thin-fi lm transistors >1 cm 2 V −1 s −1 ; [ 34 ] (2) good crystallization behavior, stability against decomposition and oxidation at high temperature, and moderate photoluminescence effi ciency; [34][35][36] and (3) close surface energy matching of LES to that of NTCDA. A number of studies have investigated DIP growth on inorganic surfaces like SiO 2 [37][38][39][40][41] showing an upright crystalline orientation with little in-plane ordering. The 3D growth of upright DIP has also been observed on organic layers including F 16 CoPc and F 16 CuPc [ 42,43 ] with inplane disorder.A typical series of refl ection high-energy electron diffraction (RHEED) patterns for the growth of NTCDA/DIP alternating layer structures grown at room temperature are shown in Figure 1 . Bulk structures for NTCDA and DIP are shown in Figure S1 in the Supporting Information. Although there The presence of excitons in organic semiconductors at room temperature distinguishes them from traditional se...

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Nonpolar growth and characterization of a-plane InGaN/GaN quantum well structures with different indium compositions

Cited by 5 publications

References 24 publications

Quantitative parameters for the examination of InGaN QW multilayers by low-loss EELS

Quantitative parameters for the examination of InGaN QW multilayers by low-loss EELS

Evaluation of growth methods for the heteroepitaxy of non-polar(112¯0)GAN on sapphire by MOVPE

Organic Step Edge Driven Heteroquasiepitaxial Growth of Organic Multilayer Films

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