Spatially Indirect Excitons in Self-Assembled Ge/Si Quantum Dots

Abstract

Using eletron filling modulation absorption spectroscopy we study the effect of quantum dot charging on the interband excitonic transitions in type-II Ge/Si heterostructures containing pyramidal Ge nanocrystals. In contrast to type-I systems the ground state absorption is found to be blue shifted when exciton-hole and exciton-exciton complexes are formed. For a positively charged dot we argue that this is the consequence of dominance of the hole-hole and electron-electron interactions conmpared to the electron-hole interaction due to the spatial separation of the electron and hole. When two excitons are excited in the dot the electrons are found to be spatially separated and have different single-particle quantization energies. This is the reason why the biexciton absorption is blue shifted as compared to a single exciton.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2001
Accession Number
ADP013172

Entities

People

  • A. I. Nikiforov
  • A. I. Yakimov
  • A. V. Dvurechenskii
  • A. V. Nenashev
  • N. P. Stepina

Organizations

  • Russian Academy of Sciences

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Absorption
  • Absorption Spectra
  • Electron Holes
  • Electrons
  • Energy Bands
  • Energy Gaps
  • Excitons
  • Exclusion Principle
  • Ground State
  • Heterojunctions
  • Optical Pumping
  • Pumps
  • Quantum Dots
  • Quantum Wells
  • Semiconductor Physics
  • Semiconductors
  • Transitions

Fields of Study

  • Physics

Readers

  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.

Technology Areas

  • Microelectronics
  • Quantum Computing
  • Quantum Science - Quantum Dots