Temperature-dependent Raman investigation of rolled up InGaAs/GaAs microtubes

Raul D. Rodriguez, Evgeniya Sheremet, Dominic J. Thurmer, Daniel Lehmann, Ovidiu D. Gordan, Falko Seidel, Alexander Milekhin, Oliver G. Schmidt, Michael Hietschold, Dietrich R.T. Zahn

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15 Citations (Scopus)

Abstract

Large arrays of multifunctional rolled-up semiconductors can be mass-produced with precisely controlled size and composition, making them of great technological interest for micro- and nano-scale device fabrication. The microtube behavior at different temperatures is a key factor towards further engineering their functionality, as well as for characterizing strain, defects, and temperature-dependent properties of the structures. For this purpose, we probe optical phonons of GaAs/InGaAs rolled-up microtubes using Raman spectroscopy on defect-rich (faulty) and defect-free microtubes. The microtubes are fabricated by selectively etching an AlAs sacrificial layer in order to release the strained InGaAs/GaAs bilayer, all grown by molecular beam epitaxy. Pristine microtubes show homogeneity of the GaAs and InGaAs peak positions and intensities along the tube, which indicates a defect-free rolling up process, while for a cone-like microtube, a downward shift of the GaAs LO phonon peak along the cone is observed. Formation of other type of defects, including partially unfolded microtubes, can also be related to a high Raman intensity of the TO phonon in GaAs. We argue that the appearance of the TO phonon mode is a consequence of further relaxation of the selection rules due to the defects on the tubes, which makes this phonon useful for failure detection/prediction in such rolled up systems. In order to systematically characterize the temperature stability of the rolled up microtubes, Raman spectra were acquired as a function of sample temperature up to 300°C. The reversibility of the changes in the Raman spectra of the tubes within this temperature range is demonstrated.

Original languageEnglish
Pages (from-to)1-5
Number of pages5
JournalNanoscale Research Letters
Volume7
DOIs
Publication statusPublished - 18 Dec 2012
Externally publishedYes

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Keywords

  • Dependent Raman spectroscopy
  • Gallium arsenide
  • Gallium arsenide TO phonon
  • Microtubes
  • Raman imaging
  • Raman spectroscopy defects
  • Rolled up tubes
  • Strain imaging

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Rodriguez, R. D., Sheremet, E., Thurmer, D. J., Lehmann, D., Gordan, O. D., Seidel, F., Milekhin, A., Schmidt, O. G., Hietschold, M., & Zahn, D. R. T. (2012). Temperature-dependent Raman investigation of rolled up InGaAs/GaAs microtubes. Nanoscale Research Letters, 7, 1-5. https://doi.org/10.1186/1556-276X-7-594