Anisotropic thermal conductivity of 4H and 6H silicon carbide measured using time-domain thermoreflectance

Qian, Xin; Jiang, Puqing; Yang, Ronggui

doi:10.1016/j.mtphys.2017.12.005

Cited by 108 publications

(85 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19 The uncertainties of Kz, K||(θ) and G are then estimated using a multivariate error propagation formalism based on Jacobi matrices, which was first developed by Yang et al 20 and widely used in some related works. [21][22][23][24] The effect of the signal noise, manifested as the standard deviation σ between the measured data points and the thermal model prediction, is also included in the estimated uncertainty. Figure 1(d) shows that from a typical elliptical-beam TDTR measurement, Kz and K||(θ) of β-Ga2O3 can usually be determined with an uncertainty of 11% and 15%, respectively.…”

Section: Textmentioning

confidence: 99%

Three-dimensional anisotropic thermal conductivity tensor of single crystalline β-Ga2O3

Jiang

Qian

et al. 2018

Applied Physics Letters

Self Cite

110

View full text Add to dashboard Cite

β-Ga2O3 has attracted considerable interest in recent years for high power electronics, where thermal properties of β-Ga2O3 play a critical role. The thermal conductivity of β-Ga2O3 is expected to be three-dimensionally (3D) anisotropic due to the monoclinic lattice structure. In this work, the 3D anisotropic thermal conductivity tensor of a (010)-oriented β-Ga2O3 single crystal was measured using a recently developed elliptical-beam time-domain thermoreflectance (TDTR) method. Thermal conductivity along any direction in the (010) plane as well as the one perpendicular to the (010) plane can be directly measured, from which the 3D directional distribution of the thermal conductivity can be derived. Our measured results suggest that at room temperature, the highest in-plane thermal conductivity is along a direction between [001] and [102], with a value of 13.3±1.8 W m -1 K -1 , and the lowest in-plane thermal conductivity is close to the [100] direction, with a value of 9.5±1.8 W m -1 K -1 . The through-plane thermal conductivity, which is along the [010] direction, has the highest value of 22.5±2.5 W m -1 K -1 among all the directions.Temperature-dependent thermal conductivity of β-Ga2O3 was also measured and compared with a theoretical model calculation to understand the temperature dependence and the role of impurity scattering. a xbli35@hust.edu.cn b Ronggui.Yang@Colorado.Edu

show abstract

Section: Textmentioning

confidence: 99%

Three-dimensional anisotropic thermal conductivity tensor of single crystalline β-Ga2O3

Jiang

Qian

et al. 2018

Applied Physics Letters

Self Cite

110

View full text Add to dashboard Cite

show abstract

“…Since these two sources of uncertainty are independent of each other, the total uncertainty for the Kx is determined as 2 2 18.5 9 % 21% is slightly lower than a first-principles calculation in literature (62 W m -1 K -1 ) 35 but is consistent with another TDTR measurement of Kz of ZnO [0001] (55 W m -1 K -1 ) 29 , which has its c-axis along the through-plane direction. [11][12][13][14][15][16][17][18][19][20] with the short radius of the elliptical beam oriented to be (a) parallel to and (b) perpendicular to the c-axis of ZnO, respectively. The curves of 30% bounds on the best-fitted thermal conductivity values are also included as a guide of reading to the sensitivity of the signals.…”

Section: Comparison Of the Two Methods Via Experimental Demonstrmentioning

confidence: 99%

“…The curves of 30% bounds on the best-fitted thermal conductivity values are also included as a guide of reading to the sensitivity of the signals. Figure 10 shows a summary of the in-plane thermal conductivity tensor of ZnO [11][12][13][14][15][16][17][18][19][20] measured by the beam-offset method and the elliptical-beam method under their optimal experimental conditions, respectively. Overall, these two methods compare relatively well with each other, with the measured in-plane thermal conductivities within the error bars.…”

Section: Comparison Of the Two Methods Via Experimental Demonstrmentioning

confidence: 99%

“…We then compare the two techniques under their optimal experimental conditions by measuring the in-plane thermal a) Electronic mail: Ronggui.Yang@Colorado.Edu of both methods in measuring the in-plane anisotropic thermal conductivity. In the end, the two methods are compared by measuring the in-plane thermal conductivity tensor of a ZnO [11][12][13][14][15][16][17][18][19][20] sample.…”

mentioning

confidence: 99%

See 1 more Smart Citation

A new elliptical-beam method based on time-domain thermoreflectance (TDTR) to measure the in-plane anisotropic thermal conductivity and its comparison with the beam-offset method

Jiang

Qian

Yang

2018

Review of Scientific Instruments

Self Cite

View full text Add to dashboard Cite

Materials lacking in-plane symmetry are ubiquitous in a wide range of applications such as electronics, thermoelectrics, and high-temperature superconductors, in all of which the thermal properties of the materials play a critical part. However, very few experimental techniques can be used to measure in-plane anisotropic thermal conductivity. A beam-offset method based on timedomain thermoreflectance (TDTR) was previously proposed to measure in-plane anisotropic thermal conductivity. However, a detailed analysis of the beam-offset method is still lacking. Our analysis shows that uncertainties can be large if the laser spot size or the modulation frequency is not properly chosen. Here we propose an alternative approach based on TDTR to measure in-plane anisotropic thermal conductivity using a highly elliptical pump (heating) beam. The highly elliptical pump beam induces a quasi-one-dimensional temperature profile on the sample surface that has a fast decay along the short axis of the pump beam. The detected TDTR signal is exclusively sensitive to the in-plane thermal conductivity along the short axis of the elliptical beam.By conducting TDTR measurements as a function of delay time with the rotation of the elliptical pump beam to different orientations, the in-plane thermal conductivity tensor of the sample can be determined. In this work, we first conduct detailed signal sensitivity analyses for both techniques and provide guidelines in determining the optimal experimental conditions. We then compare the two techniques under their optimal experimental conditions by measuring the in-plane thermal a) Electronic mail: Ronggui.Yang@Colorado.Edu of both methods in measuring the in-plane anisotropic thermal conductivity. In the end, the two methods are compared by measuring the in-plane thermal conductivity tensor of a ZnO [11][12][13][14][15][16][17][18][19][20] sample. II. METHODOLOGIESBoth the elliptical-beam method and the beam-offset method are based on TDTR, which is a powerful and versatile technique that has been applied to measure thermal properties of a wide range of thin films, 14-16 multilayers, 17,18 nanostructured and bulk materials, 19,20 and their interfaces. 21-23 TDTR uses two synchronized light sources, referred to as the pump (heating) and the probe (sensing) beams. The pump beam deposits a periodic heat flux on the sample surface and induces a temperature change in the sample, which is then monitored by measuring the change in the intensity of the reflected probe beam. A schematic diagram of a typical TDTR system is shown in Figure 1(a). More details of the system implementation have been described elsewhere. [24][25][26][27][28][29] Particularly, there are two features of the system relevant to this work that are worth mentioning here: (1) The polarizing beam splitter (PBS) in front of the objective lens is gimbal-mounted so that the pump beam can be steered to enable the operation of the beam-offset method while the position of the probe beam is unaffected. (2) A pair of cylindrical lenses can b...

show abstract

“…Advanced by the silicon (Si) industry, techniques to grow single crystals to certain dimensions and with specific electrical, optical, or thermal properties are both the basis for academic research and instrumental to the development of practical devices. Increasingly greater numbers of useful semiconducting materials, e.g., silicon carbide (SiC) [1][2][3] and gallium arsenide (GaAs) 4 , have benefited from the development of such production techniques and are now widely used in daily life. With the development of modern supercomputers, additional findings on novel and existing advanced materials from first-principles calculations are being investigated 5 .…”

mentioning

confidence: 99%

Effect of nucleation sites on the growth and quality of single-crystal boron arsenide

Gamage

Chen

et al. 2019

Materials Today Physics

View full text Add to dashboard Cite

Boron arsenide (BAs) has been the least investigated cubic III-V compound, but it has recently attracted significant attention since the confirmation of its unusually high thermal conductivity above 1000 W m -1 K -1 . However, determining how to achieve growth of a BAs single crystal on the centimeter scale remains unsolved, which strongly limits further research into, and potential applications of, this interesting material. Here we report our technique to grow a 7-mm-long BAs single crystal via the chemical vapor transport method by applying an additional nucleation site.The different thermal conductivity values obtained from BAs single crystals grown on nucleation sites of different compositions show the importance of choosing the proper nucleation-site material.We believe these findings will inspire further research into the growth of this unique semiconductor.

show abstract

Anisotropic thermal conductivity of 4H and 6H silicon carbide measured using time-domain thermoreflectance

Cited by 108 publications

References 38 publications

Three-dimensional anisotropic thermal conductivity tensor of single crystalline β-Ga2O3

Three-dimensional anisotropic thermal conductivity tensor of single crystalline β-Ga2O3

A new elliptical-beam method based on time-domain thermoreflectance (TDTR) to measure the in-plane anisotropic thermal conductivity and its comparison with the beam-offset method

Effect of nucleation sites on the growth and quality of single-crystal boron arsenide

Contact Info

Product

Resources

About