Size tunable strain and interfacial engineering of germanium quantum dots

Po Hsiang Liao, Ting Chia Hsu, Tzu Hsuan Cheng, Tzu Min Hsu, Pei-Wen Li

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Spherical Ge quantum dots (QDs) of desire sizes and locations within the Si-containing layers has been demonstrated using thermal oxidation of SiGe nanopillars over buffer Si3N4 on the Si substrate. Local environment material of SiO2 imposes large stress onto the Ge QD, and the compressive strain progressively increases from 0.5 to 4% with a decrease in the QD size from 110 to 60nm. Such a high pressure of 1-4.5 GPa makes a striking transition in the crystalline structure from indirect bandgap diamond to direct bandgap tetragonal for Ge as evidenced by a significant blue shift in the LO phonon Raman lines and diffraction patterns (DPs), when decreasing the QD size. Remarkably, an opposite, red shift of the Raman lines is observed from the Ge QDs when removing the encapsulated layer of SiO2 from the QDs, indicating the QD experiencing a size-dependent tensile strain. This indicates that strain engineering on the Ge QDs is tunable by the QD size and their interactions with local environments.

Original languageEnglish
Title of host publication2014 Silicon Nanoelectronics Workshop, SNW 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479956777
StatePublished - 4 Dec 2015
EventSilicon Nanoelectronics Workshop, SNW 2014 - Honolulu, United States
Duration: 8 Jun 20149 Jun 2014

Publication series

Name2014 Silicon Nanoelectronics Workshop, SNW 2014


ConferenceSilicon Nanoelectronics Workshop, SNW 2014
Country/TerritoryUnited States


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