Size-Selective Raman Scattering in Self-Assembled Ge/Si Quantum Dot Superlattices

Abstract

Self-organised Ge quantum dot (QD) superlattices having properties of two and zero dimensional structures were investigated by Raman spectroscopy. Longitudinal optical Ge (LO) and Ge-Si (L) phonons and folded acoustic (LA) phonons superimposed with a strong continuous emission were studied under resonant conditions. The measured phonon frequencies of folded LA phonons up to 15th order are in a good agreement with those calculated using the Rytov model. The low frequency continuous emission can be explained in terms ofa breakdown of crystal momentum conservation for resonant Raman processes involving acoustic phonons. A frequency enlargement of continuous emission band and a downward shift of LO Ge phonons with increasing excitation energy (2.54-2.71 eV) are attiibuted to electron and phonon size-confinement in the small Ge QDs resonantly contributing to the scattering process.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2001
Accession Number
ADP013174

Entities

People

  • A. G. Milekhin
  • A. I. Nikiforov
  • D. R. Zahn
  • O. P. Pchelyakov
  • S. Schulze

Organizations

  • Russian Academy of Sciences

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Crystal Lattice Vibrations
  • Emission
  • Excitation
  • Frequency
  • Geometry
  • High Resolution
  • Momentum Transfer
  • Phonons
  • Quantum Dots
  • Raman Scattering
  • Raman Spectra
  • Raman Spectroscopy
  • Scattering
  • Semiconductor Physics
  • Semiconductors
  • Spectra
  • Spectroscopy

Fields of Study

  • Materials science

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Materials Science and Engineering.
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.

Technology Areas

  • Microelectronics
  • Quantum Computing