Abstract
Thermal conductivity (k(T)) of Ge quantum dots (QDs) embedded in SiO 2 was investigated at T = 100-400 K. The Ge QD/SiO2 system appears to have much lower k(T) than their counterparts of bulk Ge and SiO 2, and the reduction factor increases with the surface-to-volume ratio of the QD in SiO2. Attendant to reduced magnitude includes delayed Umklapp decline and weaker dependence on temperature for k(T). Effective medium analysis suggests the reduction in k primarily comes from the decreased group velocity thanks to the QD inclusion that induces interfacial stress on SiO2, phonon confinement, and boundary scatterings.
Original language | English |
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Article number | 251913 |
Journal | Applied Physics Letters |
Volume | 101 |
Issue number | 25 |
DOIs | |
State | Published - 17 Dec 2012 |