Embedded GaN nanostripes on <i>c</i>‐sapphire for DFB lasers with semipolar quantum wells

Leute, Robert A. R.; Heinz, Dominik; Wang, Junjun; Meisch, Tobias; Müller, Marcus; Schmidt, Gordon; Metzner, Sebastian; Veit, Peter; Bertram, F.; Christen, J.; Martens, Martin; Wernicke, Tim; Kneissl, Michael; Jenisch, Stefan; Strehle, Steffen; Rettig, Oliver; Thonke, Klaus; Scholz, F.

doi:10.1002/pssb.201552277

Cited by 5 publications

(2 citation statements)

References 29 publications

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“…Much better defined structures (Fig. right) have then been obtained by nano‐imprint lithography () and electron beam lithography (). Indeed, even on the side facets of such small stripes having a height of only about 200 nm, semipolar single and double quantum wells were grown ().…”

Section: Sub‐micrometer Structuresmentioning

confidence: 99%

Semipolar GaN‐based heterostructures on foreign substrates

Scholz

Caliebe

Gahramanova

et al. 2015

Physica Status Solidi (b)

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This paper reviews our recent investigations about semipolar GaN‐based optoelectronic heterostructures grown on foreign substrates. Two basically different approaches are discussed, both making use of epitaxial growth in the polar c‐direction to minimize any crystalline defects. By selective area growth, stripes with triangular cross‐section have been formed with semipolar side‐facets, on which quantum well and electroluminescence test structures have been deposited. By careful optimisation of many growth parameters, we could drastically increase the growth temperature of GaInN quantum wells emitting beyond 500 nm. In the second approach, the GaN growth starts on inclined sapphire c‐planes, which form the side facets of trenches etched into the substrates. After coalescence, planar semipolar GaN layers can be achieved. We investigated various sapphire wafer orientations leading to {112‾2}, {101‾1}, and {202‾1} layers. After careful optimisation with a major focus on the decrease of the stacking fault density, we have also investigated the doping behaviour of such semipolar structures. Eventually, full electroluminescence test structures could be grown.

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Section: Sub‐micrometer Structuresmentioning

confidence: 99%

Semipolar GaN‐based heterostructures on foreign substrates

Scholz

Caliebe

Gahramanova

et al. 2015

Physica Status Solidi (b)

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“…For conventional device processing a planarization of the surface is favorable. To achieve the planarization of the three‐dimensional structures a shrinking of the semipolar active region to nanometer scale is essential .…”

Section: Introductionmentioning

confidence: 99%

Nanoscale cathodoluminescene imaging of III‐nitride‐based LEDs with semipolar quantum wells in a scanning transmission electron microscope

Müller

Schmidt

Metzner

et al. 2015

Physica Status Solidi (b)

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The optical and crystalline properties of a c‐plane GaN‐based LED structure with embedded semipolar InGaN quantum wells (QW) were investigated using highly spatially resolved cathodoluminescence spectroscopy (CL) directly performed in a scanning transmission electron microscope (STEM). Direct correlation of the cross‐sectional STEM image with the simultaneously recorded spatially resolved CL mapping at room‐temperature reveals the most intense emission coming from the semipolar InGaN QWs. We observe an inhomogeneous wavelength distribution due to local indium fluctuations and varying QW thickness. In contrast, the donor‐acceptor pair recombination (DAP) becomes the dominating luminescence process at 16 K resulting in a superposition of the DAP luminescence and the InGaN QW emission.

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The role of surface diffusion and wing tilt in the formation of localized stacking faults in high In-content InGaN MQW nanostructures

Nakajima

Dapkus

2016

Applied Physics Letters

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Yellow and green emitting multiple quantum well structures are grown on nanostripe templates with {10-11} facets. SEM and cathodoluminescence measurements show a correlation between rough surface morphology near the bottom of the stripes and non-radiative recombination centers. Transmission electron microscopy (TEM) analysis shows that these surface instabilities are a result of stacking faults generated from the quantum well (QW) regions near the bottom of the pyramid that propagate to the surface. HRTEM images show that the stacking faults are I1 type which is formed by removal of one half basal plane to relieve the compressive strain in the InGaN QW. Thicker QWs near the bottom as a result of growth rate enhancement due to the surface diffusion of the precursors from the mask regions cause increased strain. Additionally, the compressive strain induced by the bending of the nanostructure towards the growth mask further increases the strain experienced by the QW thereby causing the localized defect generation.

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Embedded GaN nanostripes on c‐sapphire for DFB lasers with semipolar quantum wells

Cited by 5 publications

References 29 publications

Semipolar GaN‐based heterostructures on foreign substrates

Semipolar GaN‐based heterostructures on foreign substrates

Nanoscale cathodoluminescene imaging of III‐nitride‐based LEDs with semipolar quantum wells in a scanning transmission electron microscope

The role of surface diffusion and wing tilt in the formation of localized stacking faults in high In-content InGaN MQW nanostructures

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