Thermal conductivity of nanostructured SixGe1−x in amorphous limit by molecular dynamics simulation
Abstract
We report the thermal conductivity of amorphous SixGe1−x compound calculated versus composition and temperature. The result sets the minimum value of thermal conductivity which is achievable by nanostructuring. We employed molecular dynamics with Tersoff's potential for the calculations. It was found that, contrary to the crystalline SixGe1−x, the thermal conductivity of amorphous phase is a weak function of the material composition. For the most popular composition Si0.8Ge0.2, the thermal conductivity of the amorphous phase is less than 1 W m−1 K−1 with small reduction as the temperature increases from 300 K to 1400 K. The thermal conductivity of amorphous SixGe1−x for any value of x is approximately an order of magnitude smaller than the minimum thermal conductivity of crystalline SixGe1−x alloy, which occurs near x = 0.5. It is known that alloying with germanium is more efficient than nanostructuring to reduce the thermal conductivity of silicon; however, it was found that the amorphization process is even more effective than alloying for that purpose. It was also shown that the reduction of the thermal conductivity of silicon due to alloying with germanium is more efficient in crystalline phase than in amorphous phase.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2015
- Source ID
- 10.1063/1.4921536
Entities
People
- Amin Nozariasbmarz
- Daryoosh Vashaee
- Jerzy S. Krasiński
- Payam Norouzzadeh
Organizations
- Army Research Office
- National Science Foundation
- North Carolina State University
- Oklahoma Center for the Advancement of Science and Technology
- Oklahoma State University–Stillwater