Details

Autor(en) / Beteiligte

• Ci, Penghong
• Sun, Muhua
• Upadhyaya, Meenakshi
• Song, Houfu
• Jin, Lei
• Sun, Bo
• Jones, Matthew R
• Ager, Joel W
• Aksamija, Zlatan
• Wu, Junqiao

Titel

Giant Isotope Effect of Thermal Conductivity in Silicon Nanowires

Ist Teil von

• Physical review letters, 2022-02, Vol.128 (8), p.085901-085901, Article 085901

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2022

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• Isotopically purified semiconductors potentially dissipate heat better than their natural, isotopically mixed counterparts as they have higher thermal conductivity (κ). But the benefit is low for Si at room temperature, amounting to only ∼10% higher κ for bulk ^{28}Si than for bulk natural Si (^{nat}Si). We show that in stark contrast to this bulk behavior, ^{28}Si (99.92% enriched) nanowires have up to 150% higher κ than ^{nat}Si nanowires with similar diameters and surface morphology. Using a first-principles phonon dispersion model, this giant isotope effect is attributed to a mutual enhancement of isotope scattering and surface scattering of phonons in ^{nat}Si nanowires, correlated via transmission of phonons to the native amorphous SiO_{2} shell. The Letter discovers the strongest isotope effect of κ at room temperature among all materials reported to date and inspires potential applications of isotopically enriched semiconductors in microelectronics.