Thermal conductivity of germanium doped with silicon, tin, and aluminium

Abstract

The thermal conductivity of Ge doped with electroneutral impurities, Si, Sn and the acceptor impurity, Al, is investigated in the temperature range 80 to 400 K. It is established that at equal impurity concentrations the temperature dependence of the thermal conductivity in Ge doped with the electroactive impurity Al, is weaker than in Ge doped with electroneutral impurities, Si and Sn. The effect of impurity concentration on the additional thermal resistance at T = 300 K is described by the expression δW ∼ cn, where n ≈ 0.5 for all systems Ge:Si, Ge:Sn, Ge: Al investigated. The results obtained are analysed on the basis of existing theories on thermal conductivity.

Phase‐Change Materials: Vibrational Softening upon Crystallization and Its Impact on Thermal Properties

“…In the crystalline phase, the combination of a large bulk modulus and a large thermal coefficient of thermal expansion coefficient leading to a large anharmonicity contributes, together with the very low Debye temperature, to the extremely low thermal conductivity, which is proportional to the third power of the Debye temperature and inversely proportional to the anharmonicity γ 46. These parameters hence contribute to the low thermal conductivity of Ge 2 Sb 2 Te 5 of around 0.44 W K −1 m −1 , while semiconductors with ordinary covalent bonding such as Si (156 W K −1 m −1 ),47 Ge (60 W K −1 m −1 ),19 or GaAs (45 W K −1 m −1 )20 all have much higher thermal conductivity.…”

“…Both the low value of the thermal conductivity in crystalline phase‐change materials and the small difference between the amorphous and crystalline state are quite remarkable and point to unique lattice properties. Ordinary covalent semiconductors, even those consisting of heavy elements, show a significantly larger thermal conductivity in the crystalline state, like Ge (60 W K −1 m −1 ),19 GaAs (45 W K −1 m −1 20), InSb (20 W K −1 m −1 21), and GaSb (60 W K −1 m −1 21). For these materials, the thermal conductivity changes substantially upon crystallization.…”

Thermal conductivity of germanium crystals with different isotopic compositions

“…In the past four decades, however, only few investigations have been reported on the effect of isotopic composition on thermal conductivity. Measurements for LiF, 36 Ge, 21,37,38 and diamond 22,23,39,40 were performed in the temperature range between 4 K and room temperature or higher. Studies of solid 4 He, 41,42 LiF, 36,43,44 Ne, 45,46 and B 4 C, 47 cover only a rather limited temperature range.…”

First-principles study on the lattice dynamics and thermodynamic properties of Cu 2 GeSe 3

“…higher thermal conductivities: 58 Wm −1 K −1 for Ge and 18 Wm −1 K −1 for ZnSe at room temperature [8,9].…”