The role of nanosize dependence of dislocation and surface roughness concentrations to calculate lattice thermal conductivity in In_0.53Ga_0.47As nanofilms

ABSTRACT

Systematic empirical relations were established for the nanosize-dependent surface roughness, $\epsilon (D)$, dislocations, $N_D(D)$, and effective length to examine their effects on the temperature-dependent lattice thermal conductivity (LTC) within the framework of the Morelli-Callaway model for In_0.53Ga_0.47As alloy films with thicknesses ranging from 10 to 70 and 1400 nm, the latter representing the material’s bulk state. The results were analyzed for film thicknesses of 2, 5, 200, and 500 nm, under the assumption that electrons and impurities are unaffected by nanosize, while a small alloy parameter significantly and sensitively alters the LTC curve in medium and high-temperature regions. According to these new findings, and considering phonon scattering processes, the LTC’s temperature dependence is sufficiently reduced at the nanoscale and fits well with the available reported experimental findings. It was also discovered that the LTC’s peak maximum value and its corresponding temperature are influenced by the film’s dislocation concentration, surface roughness, and thickness. Unravelling the complex interplay between nanosize-dependent dislocation and surface roughness concentrations becomes critical for a thorough knowledge when examining the delicate nuances of LTC in In_0.53Ga_0.47As nanofilms. Finally, the Morelli-Callaway-based model has been modified to calculate LTC for nanofilms without fitting parameters, provided their related bulk state values are known.

KEYWORDS:

• Lattice thermal conductivity
• In_0.53Ga_0.47As
• nanofilms
• phonon-scattering
• surface roughness
• lattice dislocation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was fully funded by the College of Science at the University of Salahaddin-Erbil (Grant number 3/1/6464-992020).