Sylvia Hagedorn

GaN substrates by HVPE

The availability of GaN substrates is crucial for GaN-based laser diodes. Also high performance LEDs ask for high quality substrates. Methods for growth of bulk GaN are reviewed with a focus on hydride vapour phase epitaxy (HVPE), which currently is the method used for the production of GaN substrates. Also the ammonothermal approach is briefly discussed. Both approaches still have to overcome limitations before mass-production at affordable prices is feasible. These limitations are related to the maximum growth rate yielding high quality material as well as the boule length that can be achieved together with high material quality.

Hydride Vapor-Phase Epitaxy of c-Plane AlGaN Layers on Patterned Sapphire Substrates

Growth of AlxGa1−xN layers by hydride vapor-phase epitaxy on patterned sapphire substrates is investigated. The pattern consists of honeycombs which by their orientation and size promote the formation of coalesced c-plane-oriented AlxGa1−xN layers with reduced crack density. The orientation of parasitic crystallites in the honeycomb openings is investigated using scanning electron microscopy and electron back-scatter diffraction. Crystallites with their [

Predominant growth of non-polar a-plane (Al,Ga)N on patterned c-plane sapphire by hydride vapor phase epitaxy

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The effects of magnesium doping on the modal loss in AlGaN-based deep UV lasers

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From heterostructure design to package: development of efficient and reliable UVB LEDs (Conference Presentation)

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Effect of Electron Blocking Layer Doping and Composition on the Performance of 310 nm Light Emitting Diodes

1¯.0] and [52.3] directions parallel to the vertical growth direction of the Al0.3Ga0.7N layer are observed and successfully overgrown by a 20-μm-thick fully coalesced c-plane-oriented layer.