Optoelectronic devices on bulk GaN

Figge, S.; Böttcher, T.; Dennemarck, J.; Kröger, Roland; Paskova, T.; Ḿonemar, B.; Hommel, D.

doi:10.1016/j.jcrysgro.2005.03.017

Cited by 9 publications

(5 citation statements)

References 14 publications

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“…Zero‐dimensional structures, so‐called quantum dots, have the potential to overcome the problems associated with the polar nature of this crystal plane 24. At our institute metal organic vapour epitaxy (MOVPE) has successfully been applied for the realization of InGaN/GaN based light emitting devices over the last years 25, 26. In the following, we will present detailed results on a combined STM, transmission electron microscopy (TEM), and micro‐photoluminescence (µ‐PL) study aiming to identify MOVPE growth conditions most suitable for the growth of InGaN quantum dots embedded in GaN.…”

Section: Introductionmentioning

confidence: 99%

Cleaning and growth morphology of GaN and InGaN surfaces

Falta

Schmidt

Gangopadhyay

et al. 2011

Physica Status Solidi (b)

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The structure and chemistry of clean GaN surfaces and InGaN thin films and nanostructures grown by metal organic vapour pressure epitaxy (MOVPE) has been studied by means of X-ray photoemission spectroscopy, low-energy electron diffraction as well as scanning tunneling microscopy (STM) and transmission electron microscopy. Thermal annealing strongly improves the cleanliness of samples after dry nitrogen transfer and related exposure to residual oxygen. Nitrogen plasma assisted cleaning is shown to successfully further remove carbon contaminations, while Ga deposition with subsequent desorption to is shown to be superior for an enhanced reduction of surface oxygen. Using STM, the surface morphology has been studied in dependence on major growth parameters at various stages of InGaN MOVPE growth. The formation of nano-islands is reported for different growth conditions. By means of microphotoluminescence measurements, we find samples to show strong photoluminescence from quantum-dot-like structures, however, the corresponding growth front is found to be rather flat throughout InGaN deposition. This leads to the conclusion that the formation of quantum dots does not proceed in a Stranski-Krastanov-like fashion but most likely during overgrowth.Scanning tunneling micrograph and height profile of 3.9 nm InGaN grown by MOVPE at 700 8C, after growth interruption and 1 min post-growth annealing at the growth temperature. The surface exhibits a two-dimensional islands morphology.

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Section: Introductionmentioning

confidence: 99%

Cleaning and growth morphology of GaN and InGaN surfaces

Falta

Schmidt

Gangopadhyay

et al. 2011

Physica Status Solidi (b)

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“…There are several reports in the literature presenting finite-element calculations of the heat dissipation in nitride devices grown on thermal insulating and thermal conductive GaN substrates [73]- [75]. The thermal resistance was shown to be four to five times higher in case of using sapphire.…”

Section: B Thermal Conductivitymentioning

confidence: 99%

GaN Substrates for III-Nitride Devices

2010

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| Despite the rapid commercialization of III-nitride semiconductor devices for applications in visible and ultraviolet optoelectronics and in high-power and high-frequency electronics, their full potential is limited by two primary obstacles: i) a high defect density and biaxial strain due to the heteroepitaxial growth on foreign substrates, which result in lower performance and shortened device lifetime, and ii) a strong built-in electric field due to spontaneous and piezoelectric polarization in the wurtzite structures along the well-established [0001] growth direction for nitrides. Recent advances in the research, development, and commercial production of native GaN substrates with low defect density and high structural and optical quality have opened opportunities to overcome both of these obstacles and have led to significant progress in the development of several optoelectronic and high-power devices. In this paper, the recent achievements in bulk GaN growth development using different approaches are reviewed; comparison of the bulk materials grown in different directions is made; and the current achievements in device performance utilizing native GaN substrate material are summarized.

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“…The homoepitaxial Mg-doped GaN layers were grown on thick HVPE GaN substrates by MOCVD in a Thomas Swan reactor as previously described [9]. …”

Section: Samples and Experimentsmentioning

confidence: 99%

The dominant shallow 0.225 eV acceptor in GaN

Ḿonemar

Paskov

Bergman

et al. 2006

Physica Status Solidi (b)

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We have studied the optical signatures of the Mg acceptor in GaN, using samples that are doped with Mg during MOCVD growth. In order to reduce the defect density in the material and thus achieve narrow linewidths in optical spectra we have used thick HVPE grown GaN layers as templates in the MOCVD growth. The photoluminescence (PL) spectra show two acceptor-related bound exciton peaks at 3.466 eV and 3.455 eV respectively. In the lower photon energy range the 3.27 eV emission with its LO-phonon replicas is dominant, riding on a broad background emission peaking at about 3.1 eV. These results, together with previous data in the literature, indicate that there are two acceptors in Mg-doped GaN, one dominating the optical spectra (the 3.466 eV and the 3.27 eV emissions) and another related to the 3.455 eV and the 3.1 eV emissions. We suggest that the latter is related to the Mg acceptor, while the former is a H-related complex, not necessarily involving Mg.

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Optoelectronic devices on bulk GaN

Cited by 9 publications

References 14 publications

Cleaning and growth morphology of GaN and InGaN surfaces

Cleaning and growth morphology of GaN and InGaN surfaces

GaN Substrates for III-Nitride Devices

The dominant shallow 0.225 eV acceptor in GaN

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