Anomalously low thermal conductivity and thermoelectric properties of new cationic clathrates in the Sn-In-As-I system

Single-crystal samples of cationic clathrates in the Sn-In-As-I system with different indium contents have been synthesized. Their crystal structure has been analyzed and their thermoelectric properties have been measured. These compounds are found to be n-type semiconductors with high absolute values of the Seebeck coefficient (S = 400–600 μV/K) and anomalously low thermal conductivity (κ ≤ 0.4 W/(m/K) at 300 K, which is characteristic of amorphous materials. The reasons for the anomalously low thermal conductivity of these semiconductors are discussed and ways for optimizing their thermoelectric properties are shown.     

Thermoelectric properties of bismuth telluride nanocomposites with fullerene

A nanocomposite material consisting of Bi₂Te₃ nanocrystals 30 nm in size coated with a C₆₀ molecule layer is obtained. The Hall effect and thermoelectric properties of the composite are studied. The acceptor effect of fullerene in both p- and n-type Bi₂Te₃ is detected. Nanocomposite material properties are modified due to the formation of layers of fullerene charged molecules: the nanocomposite thermopower increases, while the thermal conductivity decreases.     

Realization of a New Definition of Kelvin on State Primary Standard of Temperature Unit Get 35-2021 in the Temperature Range from 0.3 To 273.16 K

Measurement Techniques - The article describes the composition and metrological characteristics of the State Primary Standard of temperature unit – kelvin – in the range from 0.3 K to...     

Persistent IR photoconductivity in InAs/GaAs structures with QD layers

Persistent IR photoconductivity in InAs/GaAs structures with layers of QDs with a p-and n-type conductivity was studied. At the initial stage, after the illumination is switched off, the relaxation of photoconductivity follows a logarithmic law. The relaxation time depends on temperature; it decreases as temperature increases. A simple model of photoconductivity relaxation, based on thermal activation of carriers from the QD layer, is proposed. The model is consistent with the experimental data.