Detection of the third transition of InAs/GaAsSb quantum dots

Keun Yong Ban, Stephen P. Bremner, Darius Kuciauskas, Som N. Dahal, Christiana Honsberg

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We have investigated InAs quantum dots (QDs) on GaAsSb barrier layers. Low temperature photoluminescence (PL) for InAs/GaAsSb with various δ-doping levels is performed to observe interband transitions. PL spectra of heavily doped QD samples show that the electrons injected from the δ-doping plane increase the intensity of the emission peak between the electron and hole first excited states, E1H1, not observed from undoped and lightly QD samples. Time resolved photoluminescence (TRPL) data as a function of δ-doping density reveal that the introduction of a δ-doping plane in the GaAsSb barrier decreases a carrier lifetime making recombination between ground states in QD area faster. As an evidence of carriers more injected from a δ-doping plane an Arrhenius fitting curve taken from temperature dependent PL indicates that the doped samples have the greater thermal activation energies than those of the lightly doped samples. Additionally, intersubband transitions of 20 multiple InAs QDs embedded in GaAsSb barriers are experimentally determined by low temperature (77K) Fourier Transformation-Infrared Spectroscopy (FT-IR) using a multiple internal reflection technique. It is noted that there is a broad peak around about 240meV corresponding to the energy separation between the electron ground state and the continuum state in the conduction band offset (CBO). The band structure based upon an eight band k.p method confirms the experimental results observed here. Furthermore, all related physical phenomena will be discussed as well.

Original languageEnglish (US)
Title of host publicationProgram - 37th IEEE Photovoltaic Specialists Conference, PVSC 2011
Number of pages4
StatePublished - Dec 1 2011
Event37th IEEE Photovoltaic Specialists Conference, PVSC 2011 - Seattle, WA, United States
Duration: Jun 19 2011Jun 24 2011

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371


Other37th IEEE Photovoltaic Specialists Conference, PVSC 2011
Country/TerritoryUnited States
CitySeattle, WA

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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