Abstract
Room-temperature time-domain thermoreflectance technique (TDTR) measurements of cross-plane heat conduction across gold-graphene-silicon interfaces are presented. The graphene layers are originally grown on a copper substrate by chemical vapor deposition and later transferred to a silicon substrate in layer-by-layer fashion. We estimate the thermal boundary conductance (TBC) as a function of number of graphene layers, by fitting a layered heat conduction model that accounts for heat accumulation in the gold layer to the TDTR data, using the TBC as a free fitting parameter. The estimated TBC was found to decrease with number of graphene layers at the interface, as observed in previous TDTR measurements reported in the literature. The decrease in TBC with number of graphene layers matches the trends in the transmission coefficient of low frequency (25 GHz) coherent acoustic phonons across the interface, indicating that the interface elastic stiffness decreases with the number of graphene layers due to poor bonding between the gold film and silicon substrate.
| Original language | English (US) |
|---|---|
| Article number | 045126 |
| Journal | AIP Advances |
| Volume | 9 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2019 |
Funding
This work was supported by the Northwestern University (NU) Materials Research Science and Engineering Center (MRSEC) (NSF DMR-1121262). The authors thank Professor Sridhar Krish-naswamy in the Mechanical Engineering at NU for providing a Ti:Sapphire femtosecond laser oscillator used for the TDTR measurements. This work utilized the NU Micro/Nano Fabrication Facility (NUFAB), which is partially supported by Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the Materials Research Science and Engineering Center (DMR-1720139), the State of Illinois, and NU.
ASJC Scopus subject areas
- General Physics and Astronomy