Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: HL Poster II

HL 35.10: Poster

Wednesday, April 3, 2019, 17:30–20:00, Poster E

Structural and optical investigation of metamorphic AlInGaN barriers — •Carina Walz, Michael Jetter, and Peter Michler — IHFG, Universität Stuttgart

Nitride semiconductors are already widely used as they are key com- ponents for solid-state lightning and have the ability to cover the complete visible spectral range. A drawback in this material system is the piezoelectric effect in hetero-structures, which gets more pronounced as larger the lattice mismatch between the barrier layers and the light emitting quantum well (QW) gets. These intrinsic electric fields lead to a reduced recombination, respectively emission efficiency due to the quantum confined Stark effect (QCSE). In order to reduce this QCSE and reach higher emission efficiencies at higher In-content inside the InGaN QWs, the implementation of metamorphic aluminum-indium-gallium-nitride (AlInGaN) barriers can be advantageous. With AlInGaN barriers the strain situation and the band offsets to the QW can be adjusted in a certain range independently, thus reduce the electric field at the position of the InGaN QW.

In our contribution a sample series of quaternary nitride barriers with varying strain state from tensile to compressive with respect to the GaN layer were fabricated by metal-organic vapour-phase epitaxy (MOVPE. The structural properties of the AlInGaN layers were investigated by high-resolution x-ray diffraction (XRD) measurements. In order to examine surface defects atomic force microscopy (AFM) and scanning electron microscopy (SEM) is used. Additionally, photoluminescence spectra of the sample series were recorded.