Time domain thermoreflectance measurements and phonon gas modeling of the thermal conductivity of silicon doped indium phosphide pertinent to quantum cascade lasers
C. Perez,
D. Talreja,
J. Kirch,
S. Zhang,
V. Gopalan,
D. Botez,
B. M. Foley,
B. Ramos-Alvarado,
L. J. Mawst
Affiliations
C. Perez
Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
D. Talreja
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
J. Kirch
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
S. Zhang
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
V. Gopalan
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
D. Botez
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
B. M. Foley
Laser Thermal, Charlottesville, Virginia 22902, USA
B. Ramos-Alvarado
Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
L. J. Mawst
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
The thermal conductivity of Si-doped thin films of indium phosphide grown via metalorganic vapour-phase epitaxy at different carrier concentrations and thicknesses was measured from 80 to 450 K using time domain thermoreflectance. Additionally, phonon gas modeling was conducted to characterize the various scattering mechanisms that contribute to the thermal transport in these materials. A sensitivity analysis based on the phonon gas model showed that while thickness has a greater influence on the thermal conductivity than carrier concentration at the micron-scale for all samples, point defects due to Si-dopant atoms at carrier concentrations of ∼1019 cm−3, as well as the presence of extended defects that are most likely present due to dopant saturation, have a significant impact on thermal transport as a result of increased phonon scattering, decreasing the thermal conductivity by 40% or more.
