Macroscopic defects in GaN/AlN multiple quantum well structures grown by MBE on GaN templates
Journal article, 2009

We have used MBE to grow in AlN/GaN superlattices, with different number of periods, on 2.5-mu m-thick MOVPE-GaN templates to study the development of defects such as surface deformation due to strain. After growth the samples were studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), XRD and Fourier transform infrared spectroscopy (FT-IR). The strain increased with the number of quantum wells (QWs) and eventually caused defects such as microcracks visible by optical microscopy at four or more QW periods. High-resolution TEM images showed shallow recessions on the surface (surface deformation) indicating formation of microcracks in the MQW region. The measured intersubband (IS) absorption linewidth from a four period structure was 97 meV, which is comparable with the spectrum from a 10 period structure at an absorption energy of similar to 700 meV. This indicates that the interface quality of the MQW is not substantially affected by the presence of cracks. (C) 2008 Elsevier Ltd. All rights reserved.

Template

MBE

Surface cracks

Sapphire substrate

Intersubband

GaN

Author

Thorvald Andersson

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Xinju Liu

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

T. Aggerstam

Royal Institute of Technology (KTH)

P. Holmstrom

Royal Institute of Technology (KTH)

S. Lourdudoss

Royal Institute of Technology (KTH)

L. Thylen

Royal Institute of Technology (KTH)

Y. L. Chen

National Sun Yat-Sen University Taiwan

C. H. Hsieh

National Sun Yat-Sen University Taiwan

I. Lo

National Sun Yat-Sen University Taiwan

Microelectronics

0026-2692 (ISSN)

Vol. 40 2 360-362

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1016/j.mejo.2008.07.065

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Latest update

2/26/2018