Thermal conductivity of indium at high pressures and temperatures under shock compression

The results of investigations of the electrical and thermal conductivity of indium in the pressure range up to 27 GPa and at temperatures up to 1000 K are presented. In this pressure range, the electrical resistance of indium samples is measured under multishock compression. The equation of state constructed for indium is used to calculate the evolution of the thermodynamic parameters of indium in shock wave experiments; then, the dependences of the electrical resistivity and thermal conductivity coefficient on the volume and temperature are determined. It is demonstrated that, in the pressure and temperature ranges under investigation, the thermal conductivity coefficient of indium does not depend on temperature and its threefold increase is caused only by the change in the volume under compression.     

Thermal conductivity and electrical resistivity of bulk indium and indium embedded in 7-nm channels of porous borosilicate glass

A “porous glass + indium” nanocomposite has been prepared. The thermal conductivity κ(T) and electrical resistivity ρ(T) of the nanocomposite have been measured in the temperature range 5–300 K, and their fractions accounted for by nanoindium embedded in 7-nm channels of the porous glass have been determined. For comparison, κ and ρ of the bulk polycrystalline indium sample have been measured in the same temperature range. The electronic and phonon components of the thermal conductivity have been calculated for the nanoindium and bulk indium. It has been demonstrated that, as the result of the emergence of boundary electron and phonon scattering in the nanoindium, the electrical resistivity of this material becomes larger, and the phonon thermal conductivity, smaller than those of the bulk indium.     

THERMAL CONDUCTIVITY OF METALLIC WIRES

The effect of radial thickness on the thermal conductivity of a free standing wire is investigated. The thermal conductivity is evaluated using the Boltzmann equation. A simple expression for the reduction in conductivity due to the increase of boundary scattering is presented. A comparison is made between the experimental results of indium wires and the theoretical calculations. It is shown that this decrease of conductivity in wires is smaller than that in film where heat flux is perpendicular to the surface.     

Thermal parameters of layers and interfaces in silicon-on-diamond structures

The heat propagation at room temperature was studied in a heterostructure consisting of a polycrystalline diamond film deposited from a hydrocarbon plasma on an oriented silicon substrate. The dynamics of cooling of a thin-film indium thermometer evaporated atop the diamond film was measured following its heating by nanosecond nitrogen laser pulses. The experimental data were compared with the values calculated in the framework of the theory of thermal conductivity for multilayer systems. This analysis permitted the determination of both the thermal conductivity of the diamond film and the thermal resistance of the diamond/Si and In/diamond interfaces.     

Thermal conductivity of selenium doped with indium and iodine in the solid and liquid states

We have measured the thermal conductivity in both the solid and liquid states for two amorphous samples. The first was selenium doped with indium and the second was selenium doped with iodine. The concentration of In and I in both samples was 50000 ppm in weight, which is equal to 3.33% for indium and 3.02% for iodine additives in atomic percent. The measurements were taken in the temperature range from 100 to 470°C and were carried out using the concentric cylindrical wall. It was found that the thermal conductivity of both samples is of the phonon type; its temperature dependence follows the relation K _ph T ^–1, and can be explained by the influence of thermal effects on the lattice structure.     

Composition dependence of effective thermal conductivity and effective thermal diffusivity of Se100−xInx (x=0, 5, 10, 15 and 20) chalcogenide glasses

Simultaneous measurement of effective thermal conductivity (λ_e) and effective thermal diffusivity (χ_e) of twin pallets of Se_100−xIn_x (x=0,5, 10, 15, and 20) glasses, prepared under a load of 5 tons, have been made at room temperature using the Transient Plane Source (TPS) technique. The values of λ_e and χ_e were found to increase initially with the increase of concentration of In in Se-In alloy and had their maximum at 10 at.wt% of indium. For indium concentration beyond 10 at.wt% of the values of effective thermal conductivity and effective thermal diffusivity decrease linearly. This is suggestive of fact that 10 at.wt% of indium can be considered as a critical composition at which the alloy becomes, chemically ordered and maximum thermally stable than other composition. Further addition of indium in selenium decreases the values of λ_e and χ_e. The behaviour is explained on the basis of decrease of localized states and increase in disorderness for higher composition indium.     

Effect of pressure on the temperature dependence of the thermal conductivity of InSb

The dependence of the thermal conductivity of indium antimonide on temperature (in the range 300–450 K) and hydrostatic pressure (up to 0.4 GPa) has been investigated. It is shown that the phonon thermal conductivity λ_ph obeys the law T ^?n (n ≥ 1). Hydrostatic pressure affects the magnitude and temperature dependence of the thermal conductivity of InSb: with an increase in pressure, the thermal conductivity increases, while the parameter n in the dependence λ_ph ≈ T ^?n decreases.     

Size dependent ultrasonic properties of InN nanowires

The ultrasonic properties of single crystalline indium nitride nanowires (InN NWs) are studied for wire size (diameter) 6–100 nm at 300 K following the interaction potential model. Ultrasonic attenuation, ultrasonic velocity, acoustic coupling constant and thermal relaxation time are calculated using higher order elastic constants and thermal conductivity of the nanowires. The analysis of size dependent thermal relaxation time and ultrasonic properties shows that above the 20 nm diameter, InN nanowire tends towards its bulk material property. The third order polynomial is found to be best fit for size variation of thermal relaxation time. The ultrasonic attenuation as a function of size of the nanowires is found to be mainly affected by the thermal conductivity of the nanowires of different sizes.     

太赫兹波段金属线栅的紫外光控特性研究

基于氧化铟纳米薄膜及金属线栅的特性,利用紫外激光诱导以金属线栅为衬底的氧化铟纳米结构,研究其对于太赫兹偏振透射的调制特性。实验中在金属线栅上滴入溶于乙醇的氧化铟溶液,并使溶液恰好浸润在金属线栅缝隙中,同时将加热台的温度调至340 ℃,对金属线栅中的氧化铟进行热退火。结果表明,氧化铟-金属线栅线长方向与太赫兹电场偏振方向垂直时,在低强度紫外光的照射下,该样品对太赫兹的透射强度有较为明显的衰减,当紫外光功率密度为7 mW·cm-2时,样品对太赫兹的调制深度可达71%;当氧化铟-金属线栅线长方向与太赫兹电场偏振方向平行时,紫外光激发下的样品对太赫兹的调制效果明显减弱,当紫外光功率密度为7 mW·cm-2时,调制深度约为20%。氧化铟纳米薄膜中存在的氧空位,使该材料对紫外光具有特殊响应。在无紫外光照射下,样品环境中的氧气分子被吸附到氧化铟表面,由于化学反应生成O2-离子态。当用光子能量大于氧化铟禁带宽度的紫外光激发样品时,在氧化铟表面激发出电子空穴对,空穴会被氧化铟表面的O2-离子态和缺陷态束缚,从而释放电子到导带,增强了样品的电导率。在太赫兹波频段内,透过氧化铟样品的太赫兹强度与氧化铟电导率有很好的相关性。金属线栅利用金属表面可存在的自由电子的振荡, 使电场方向与线栅方向平行的太赫兹偏振光激发电子沿线栅方向振荡,当电子与金属晶格中的原子碰撞时,此偏振光发生衰减并伴随辐射;而电场方向与线栅方向垂直的太赫兹偏振光,由于周期性结构的限制,无法激发自由电子振荡, 主要表现出透射特性。结合氧化铟的表面缺陷特性,紫外光可实现作为氧化铟-金属线栅结构的光控偏振开关作用,氧化铟-金属线栅结构偏振器能很好地应用于太赫兹波频段的光控偏振调制。     

Investigation of the recombination radiation from layers of n-CdSiAs2

Complex investigations of the recombination radiation from monocrystals of p-CdSiAs₂, thermally processed together with pure indium, which is accompanied by a conversion to p n conductivity at a given depth, are reported. The effect of the thermal processing on the spectral shape and position of the maxima in the formed energy bands was determined. It was found that an increase in the time and temperature of the thermal processing is associated with a band shift in the direction of longer wavelength portion of the spectrum. The nature of the dominant radiative transitions is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 78–84, October, 1991.     

Heat resistance of the interface in the silicon-on-diamond structure at a temperature of 80 K

Heat propagation at liquid nitrogen temperature in a heterostructure consisting of a polycrystalline diamond film deposited from hydrocarbon plasma on an oriented silicon substrate is studied. A technique for measuring the cooling kinetics of a thin-film indium thermometer deposited on a diamond film after heating by nanosecond pulses of a nitrogen laser is used. The experimental data are compared with the results calculated within the theory of heat conduction for multilayer systems. The analysis performedmade it possible to simultaneously determine the thermal conductivity of the diamond film and the interfacial heat resistance of diamond/Si and In/diamond interfaces at liquid nitrogen temperature.     

Freie Weglängen im supraleitenden Zustand,im normalen Zustand und im Zwischenzustand

By size-effect measurements of the thermal conductivity of thin indium wires the mean free path of the excitations has been determined in the normal and in the superconducting state. Within the accuracy of these measurements, the mean free paths in the two states are found to be equal. — For the intermediate state the electron scattering from the interphase boundaries has been investigated both experimentally and theoretically. The experimental results can be explained with the aid of theBardeen-Cooper-Schrieffer theory of superconductivity.     

Heat transfer coefficients of liquid indium in the temperature range 470–1275 K

Thermal conductivity and thermal diffusivity coefficients of liquid indium have been determined in the range of temperatures from 470 to 1275 K by the laser flash method. Errors of heat transfer coefficients are ±(3.5–5) %. Approximating equations and tables of reference data have been developed for temperature dependence of properties. Measurement results have been compared with the data available in the literature. Temperature dependence of Lorentz number has been calculated up to 1000 K.     

Konzentration und Beweglichkeit von Elektronen in Zinkoxidkristallen mit Indium-Dotierung

The electrical conductivity and Hall effect of zinc oxide single crystals doped with indium has been measured from 5 to 300 K. Similar results to other semiconductors such as silicon and germanium are found. The temperature dependence of the measured quantities was discussed in terms of impurity band conduction and hopping conductivity.     

Electrical properties of indium implanted silicon

Electrical conductivity and Hall effect were measured from 100° to 278°K as a function of layer removal to determine the indium ionization energy and the presence of compensating centers resulting from the implantation of indium into silicon. The implants were fully annealed to reduce the influence of radiation damage. For comparison, similar measurements were performed on silicon shallow diffused with indium. Differential analysis methods were used to compute carrier concentration, mobility, and resistivity for the stripped layers. In addition, Hall measurements were performed on silicon uniformly doped with indium. In all three cases an indium energy level of 160 meV was observed. Mobility plots versus temperature were also consistent. However, significant compensation effects were noticed in the implants.     

真空铟焊的负电子亲和势砷化镓光阴极实验研究

大功率激光加载会使负电子亲和势(NEA)砷化镓(GaAs)光阴极的温度迅速升高,较高的温度对NEA GaAs光阴极的激活层造成了破坏,从而使其量子效率迅速下降。探索了基于FEL-THz装置的NEA GaAs光阴极的真空铟焊工艺,搭建了GaAs真空铟焊平台,并进行了真空铟焊后的GaAs光阴极激光与束流加载实验。研究表明,真空铟焊使GaAs与金属阴极托之间形成了紧密连接,增强了阴极与阴极托之间的热传导,减缓了阴极的温升速率,并在数瓦平均功率激光加载时将注入器中NEA GaAs光阴极的工作寿命提高了一个量级以上。     

Horizontally networked carbon nanotubes grown on Au–Fe catalyst nanoparticles

Undoped and doped indium tin oxide (ITO) with different concentrations (2, 4, and 6 mol%) of different dopants (CuO, Cr₂O₃, and ZrO₂) were prepared in the nano-size scale (19–33 nm) using Pechini method. The thermal decomposition of the precursors was studied. The electrical properties of all the prepared samples were investigated. All the investigated systems have higher conductivity than that of ITO. For ITO doped with CuO, as the concentration of CuO increases, the conductivity increases. The highest conductivity was obtained for ITO doped with 6 mol% of CuO. For ITO doped with Cr₂O₃, as the concentration of Cr₂O₃ increases the conductivity increases and above 4 mol% Cr₂O₃ the conductivity decreases. For ITO doped with ZrO₂, as the ZrO₂ concentration increases, the conductivity increases up to 4 mol% of ZrO₂ and then decreases. The band gap was detected for all the investigated systems.     

固态金属中声子热传递的分子动力学模拟研究

固态金属中的热传递是声子和自由电子共同作用的结果。自由电子引起的热导率可以通过电导率,利用Wiedemann-Franz定律得到,声子引起的热导率目前仍然不能进行实验测量,只能借助其他方法来研究。本文采用非平衡分子动力学(NEMD)方法,用镶嵌原子方法(EAM)势能模型,模拟计算了不同厚度(1.760-10.56nm)金属镍薄膜中由于声子-声子作用引起的热导率。然后根据纳米厚度金属薄膜的热导率借助关联式推到宏观尺度下由于声子-声子作用引起的热导率。结果表明,对于纳米厚度金属薄膜,由于声子-声子作用引起的热导率比块体金属镍的热导率小一个数量级;薄膜厚度越小,声子-声子作用引起的热导率越小;对于块体金属镍,由于声子-声子作用引起的热导率约占其总热导率的33.0%左右。     

Electrical conductivity and thermoelectric power of liquid selenium doped with thallium and indium

The temperature dependence of the electrical conductivity and thermoelectric power of liquid selenium with thallium and indium additives have been studied. Large variations appear in the electrical conductivity and thermoelectric power, where Tl and In additives favourp-type conduction.