Altering thermal transport by strained-layer epitaxy

作者：Majdi Tahereh; Pal Souvik; Hafreager Anders; Murad Sohail; Sahu Rakesh P; Puri Ishwar K^*

来源：Applied Physics Letters, 2018, 112(19): 194101.

DOI：10.1063/1.5022097

Since strain changes the interatomic spacing of matter and alters electron and phonon dispersion, an applied strain can modify the thermal conductivity k of a material. We show how the strain induced by heteroepitaxy is a passive mechanism to change k in a thin film. Molecular dynamics simulations of the deposition and epitaxial growth of ZnTe thin films provide insights into the role of interfacial strain in the conductivity of a deposited film. ZnTe films grow strain-free on lattice-matched ZnTe substrates, but similar thin films grown on a lattice-mismatched CdTe substrate exhibit similar to 6% biaxial in-plane tensile strain and similar to 7% uniaxial out-of-plane compressive strain. In the T= 700K-1100K temperature range, the conductivities of strained ZnTe layers decrease to similar to 60% of their unstrained values. The resulting understanding of dk/dT shows that strain engineering can be used to alter the performance of a thermal rectifier and also provides a framework for enhancing thermoelectric devices. Published by AIP Publishing.

• 出版日期2018-5-7