Thermal Conductivity of Nonmetallic Single Crystals*

Knapp, W. J.

doi:10.1111/j.1151-2916.1943.tb15185.x

Cited by 25 publications

(6 citation statements)

References 3 publications

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“…Calculations, using the analytical thermal-resistance model, indicate that the GFET thermal resistance associated with the SiO 2 layer dominates and is approximately 80% of that of the total SiO 2 /Si substrate. For comparison, the thermal conductivity of sapphire, which, for example, can be used as the GFET substrate without the SiO 2 layer, is ≈35 W/mK [49], which is significantly higher than that of SiO 2 with 1.4 W/mK [50]. In the analysis below, we simulate the GFET high-frequency performance with and without the self-heating effect.…”

Section: Resultsmentioning

confidence: 99%

Effects of Self-Heating on ${f}_{\text{T}}$ and ${f}_{\text{max}}$ Performance of Graphene Field-Effect Transistors

Bonmann

Krivic

Yang

et al. 2020

IEEE Trans. Electron Devices

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It has been shown that there can be a significant temperature increase in graphene field-effect transistors (GFETs) operating under high drain bias, which is required for power gain. However, the possible effects of self-heating on the high-frequency performance of GFETs have been weakly addressed so far. In this article, we report on an experimental and theoretical study of the effects of self-heating on dc and high-frequency performance of GFETs by introducing a method that allows accurate evaluation of the effective channel temperature of GFETs with a submicrometer gate length. In the method, theoretical expressions for the transit frequency (f T ) and the maximum frequency of oscillation (f max ) based on the small-signal equivalent circuit parameters are used in combination with the models of the field-and temperature-dependent charge carrier concentration, velocity, and saturation velocity of GFETs. The thermal resistances found by our method are in good agreement with those obtained by the solution of the Laplace equation and by the method of thermo-sensitive electrical parameters. Our experiments and modeling indicate that the self-heating can significantly degrade the f T and f max of GFETs at power densities above 1 mW/µm 2 , from approximately 25 to 20 GHz. This article provides valuable insights for further development of GFETs, taking into account the self-heating effects on the high-frequency performance.

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Section: Resultsmentioning

confidence: 99%

Effects of Self-Heating on ${f}_{\text{T}}$ and ${f}_{\text{max}}$ Performance of Graphene Field-Effect Transistors

Bonmann

Krivic

Yang

et al. 2020

IEEE Trans. Electron Devices

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“…The measurements with the stub tuner were made at 50 MHz intervals and the full curve, (d), in Figs. (2) and (3) is a composite curve of these spot frequencies. This reduction in loss was achieved at the expense of the bandwidth, which is determined by the stub tuners and is of the order of 5%.…”

Section: Resultsmentioning

confidence: 99%

“…It should be pointed out here that electrical matching reduces the transducer loss by 7 dB at best, i.e., any of the curves (a), (b), and (c) shown in Figs. (2) and (3) can be improved by this order with electrical matching, however, for the purpose of clarity, the results of matching have only been shown for specimens A and B after annealing. Specimen F was irradiated for seven hours under similar conditions to the other film, and in this case the resulting improvement in the one way transducer loss was 15 dB.…”

Section: Resultsmentioning

confidence: 99%

Effect of Neutron Irradiation on the Acoustic Performance of Evaporated CdS Films

Duncan

Hutchins

Richter

et al. 1968

Journal of Applied Physics

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Investigations have been carried out on the effects of neutron irradiation on the insertion loss of evaporated longitudinal CdS transducers operating in the frequency range 0.9-2.0 GHz. The one-way transducer loss was markedly reduced by irradiation and subsequent annealing, and the transducer bandwidth was also increased. Attempts were made to distinguish between the effects produced by thermal neutrons, fast neutrons, and gamma rays. The results suggest that neutron bombardment induces two opposing processes in a transducer. There is a significant improvement in the insertion loss due to the increase in resistivity, and an increase in the loss due to the lattice damage caused by irradiation, which effectively reduces the electromechanical coupling constant. The latter mechanism was investigated in several bulk samples of CdS. The effect of neutron irradiation on the film resistivity was investigated and it was found that the resistivity increased with irradiation. The measured resistivity was found to be a function of the thickness of the film, and this result was interpreted on the basis that the resistivity measured was an average or effective value of the mosaic of amorphous and crystalline CdS in the film, and was probably not a measure of the resistivity of the crystalline CdS.

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“…In this study, A-plane sapphire glass was used. Table 5 summarizes k 11 , k 22 , and k 33 of A-plane sapphire glasses presented in various literature [43][44][45][46][47][48]. In the numerical analysis, k 11 , k 22 , and k 33 were selected as 32.5, 23.1, and 32.5 W/(mk) from various literature.…”

Section: Specimen For Measurementmentioning

confidence: 99%

Collinear Deflection Method for the Measurement of Thermal Conductivity of Transparent Single Layer Anisotropic Material

et al. 2019

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Transparent anisotropic materials have garnered attention along with the growth of the semiconductor and display industries. Transparent anisotropic materials have the characteristic of varying electrical, optical, and thermal properties based on their crystal orientation, and many studies are being conducted on this topic. In order to utilize transparent anisotropic materials properly, thermal properties such as thermal conductivity are essentially required. However, due to the limitations of the existing thermal property measurement methods for transparent anisotropic materials, it is difficult to provide the thermal properties of transparent anisotropic materials. To address this problem, a transparent anisotropic collinear method capable of measuring the effective thermal conductivity of a transparent anisotropic material according to its crystal orientation is proposed in this paper. To this end, the internal temperature distribution of a transparent anisotropic material and the phase delay of the probe beam were theoretically derived through a numerical analysis model that uses a three-dimensional heat conduction equation. This model was applied to anisotropic thermal conductivity with orthorhombic structure. To verify the proposed method of measuring the thermal conductivity of a transparent anisotropic material, the thermal properties of 3 mm-thick A-plane sapphire glass were measured and compared with those of the existing literature. It was confirmed that the absolute errors were less than about 4 W/mk.

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Thermal Conductivity of Nonmetallic Single Crystals*

Cited by 25 publications

References 3 publications

Effects of Self-Heating on ${f}_{\text{T}}$ and ${f}_{\text{max}}$ Performance of Graphene Field-Effect Transistors

Effects of Self-Heating on ${f}_{\text{T}}$ and ${f}_{\text{max}}$ Performance of Graphene Field-Effect Transistors

Effect of Neutron Irradiation on the Acoustic Performance of Evaporated CdS Films

Collinear Deflection Method for the Measurement of Thermal Conductivity of Transparent Single Layer Anisotropic Material

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