| Autor: |
Kanedy, K., Lopez, F., Wood, M. R., Gmachl, C. F., Weimer, M., Klem, J. F., Hawkins, S. D., Shaner, E. A., Kim, J. K. |
| Předmět: |
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| Zdroj: |
Applied Physics Letters; 1/22/2018, Vol. 112 Issue 4, p1-N.PAG, 5p, 2 Diagrams, 3 Graphs |
| Abstrakt: |
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 highresolution 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 quanti- fied. 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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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