@article{7de81ceacde64054a669e32131bdadaa,
title = "Visualizing period fluctuations in strained-layer superlattices with scanning tunneling microscopy",
abstract = "We show how cross-sectional scanning tunneling microscopy (STM) may be used to accurately map the period fluctuations throughout epitaxial, strained-layer superlattices based on the InAs/InAsSb and InGaAs/InAlAs material systems. The concept, analogous to Bragg's law in high-resolution x-ray diffraction, relies on an analysis of the [001]-convolved reciprocal-space satellite peaks obtained from discrete Fourier transforms of individual STM images. Properly implemented, the technique enables local period measurements that reliably discriminate vertical fluctuations localized to within ∼5 superlattice repeats along the [001] growth direction and orthogonal, lateral fluctuations localized to within ∼40 nm along <110> directions in the growth plane. While not as accurate as x-ray, the inherent, single-image measurement error associated with the method may be made as small as 0.1%, allowing the vertical or lateral period fluctuations contributing to inhomogeneous energy broadening and carrier localization in these structures to be pinpointed and quantified. The direct visualization of unexpectedly large, lateral period fluctuations on nanometer length scales in both strain-balanced systems supports a common understanding in terms of correlated interface roughness.",
author = "K. Kanedy and F. Lopez and Wood, {M. R.} and Gmachl, {Claire F.} and M. Weimer and Klem, {J. F.} and Hawkins, {S. D.} and Shaner, {E. A.} and Kim, {J. K.}",
note = "Funding Information: Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy{\textquoteright}s National Nuclear Security Administration under Contract No. DE-NA0003525. Funding Information: This work was conceived and developed over several funding cycles supported by grants from NSF (MIRTHE NSF-ERC Cooperative Agreement No. EEC-0540832), Sandia National Laboratories, and ARO (STIR W911NF-14-1-0645, MURI W911NF-10-1-0524). The authors wish to thank Dr. Catherine Caneau (Corning Incorporated) for MOCVD growth and Dr. Wendy Sarney (Army Research Laboratory) for helpful discussions concerning TEM. Funding Information: This work was conceived and developed over several funding cycles supported by grants from NSF (MIRTHE NSF–ERC Cooperative Agreement No. EEC-0540832), Sandia National Laboratories, and ARO (STIR W911NF-14-1-0645, MURI W911NF-10-1-0524). The authors wish to thank Dr. Catherine Caneau (Corning Incorporated) for MOCVD growth and Dr. Wendy Sarney (Army Research Laboratory) for helpful discussions concerning TEM. Publisher Copyright: {\textcopyright} 2018 Author(s).",
year = "2018",
month = jan,
day = "22",
doi = "10.1063/1.5008865",
language = "English (US)",
volume = "112",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "4",
}