Stranski-Krastanov InAs/GaAsSb quantum dots coupled with sub-monolayer quantum dot stacks as a promising absorber for intermediate band solar cells

Yeongho Kim, Il Wook Cho, Mee Yi Ryu, Jun Oh Kim, Sang Jun Lee, Keun Yong Ban, Christiana Honsberg

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The optical properties of the Stranski-Krastanov (S-K) grown InAs/GaAsSb quantum dots (QDs) coupled to sub-monolayer (SML) InAs QD stacks are investigated using photoluminescence (PL) spectroscopy. The PL emission peak of the S-K QDs shifts to shorter wavelengths with increasing the number of SML stacks (NSML) due to the increasing strain fields from the SML QDs. The PL peak energy is linearly increased with increasing the cube root of excitation power, with a different ratio of the absorption coefficient to radiative recombination rate for all the QD samples. The total carrier lifetime for the S-K QDs is increased with increasing NSML, most probably caused by the increase in the ground-state transition energy of the S-K QDs. The nonmonotonic behavior of the thermal activation energy of electrons in the S-K QDs is observed due to the NSML-dependent variation of the strain and Coulombic interaction within the QDs.

Original languageEnglish (US)
Article number073103
JournalApplied Physics Letters
Volume111
Issue number7
DOIs
StatePublished - Aug 14 2017

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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