Abstract

Efficient heat dissipation to the substrate is crucial for optimal device performance in nanoelectronics. We develop a theory of electronic thermal boundary conductance (TBC) mediated by remote phonon scattering for the single-layer transition metal dichalcogenide (TMD) semiconductors MoS$_{2}$ and WS$_{2}$, and model their electronic TBC with different dielectric substrates (SiO$_{2}$, HfO$_{2}$ and Al$_{2}$O$_{3}$). Our results indicate that the electronic TBC is strongly dependent on the electron density, suggesting that it can be modulated by the gate electrode in field-effect transistors, and this effect is most pronounced with Al$_{2}$O$_{3}$. Our work paves the way for the design of novel thermal devices with gate-tunable cross-plane heat-dissipative properties.

Highlights

  • Thin two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors such as MoS2 and WS2 are promising alternative materials for the development of next-generation electronic devices [1,2]

  • We develop a theoretical model of heat dissipation by remote phonon (RP) scattering [16] and apply it to investigate the electronic thermal boundary conductance (TBC) and its dependence on the electron density, substrate material (SiO2, HfO2, and Al2O3), and temperature (T ) in two commonly studied single-layer TMDs

  • We have developed a theoretical model of electronic thermal boundary conductance (TBC) via the remote phonon scattering of electrons in single-layer MoS2 and WS2 supported on dielectric substrates

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Summary

INTRODUCTION

Thin two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors such as MoS2 and WS2 are promising alternative materials for the development of next-generation electronic devices [1,2]. The phononic TBC has been estimated using molecular dynamics (MD) simulations [5,6], elasticity theory [7,8,9], and density-functional-theory-based models [10] Another mechanism of heat dissipation is the inelastic scattering of electrons in the 2D crystal by dipoles in the dielectric substrate, a phenomenon known widely as “remote phonon (RP). Earlier theoretical and experimental work on RP heat dissipation in graphene [16,22] indicates that Gel is small for the graphene-SiO2 interface and weakly dependent on the electron density, the different electronic structure in singlelayer MoS2 and WS2 suggests that these findings for graphene may not apply to TMDs. In our paper, we develop a theoretical model of heat dissipation by RP scattering [16] and apply it to investigate the electronic TBC and its dependence on the electron density, substrate material (SiO2, HfO2, and Al2O3), and temperature (T ) in two commonly studied single-layer TMDs. We suggest applications for different substrate materials and how this electron density dependence of the TBC can be exploited to create gate-tunable thermal insulators

THEORETICAL MODEL FOR HEAT DISSIPATION BY REMOTE PHONON SCATTERING
Surface optical phonon emission and absorption rates
Electron-phonon interaction and screening
Electronic thermal boundary conductance
NUMERICAL RESULTS AND DISCUSSION
Gel dependence on electron screening
SUMMARY AND CONCLUSION
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