Thermal Transport Across Al-(AlxGa1-x)2O3 and Al-Ga2O3 Interfaces

2021 ◽  
Author(s):  
Jingjing Shi ◽  
Anusha Krishnan ◽  
A. F. M. Anhar Uddin Bhuiyan ◽  
Yee Rui Koh ◽  
Kenny Huynh ◽  
...  
Keyword(s):  
Thermal Transport ◽  
Electrical Transport ◽  
Heat Dissipation ◽  
Electrical Transport Properties ◽  
Semiconductor Interface ◽  
Theoretical Approaches ◽  
Transmission Electron ◽  
Theoretical Predictions ◽  
Different Temperatures ◽  
Bandgap Semiconductors

Abstract (AlxGa1−x)2O3 and Ga2O3 are promising wide bandgap semiconductors for application in power electronics and radio frequency devices because of their exceptional electrical transport properties. However, the heat dissipation in these devices will be limited by the ultra-low thermal conductivity of (AlxGa1−x)2O3 and Ga2O3. Previous studies showed that these devices could achieve high power density with double-sided or top-side cooling strategies. Therefore, the thermal transport across metal-(AlxGa1−x)2O3 and metal-Ga2O3 contacts is important, since heat will be conducted through the metal-semiconductor interface as a preferred pathway to extract heat from the devices. In this work, we study the thermal transport across Al-(AlxGa1−x)2O3 and Al-Ga2O3 interfaces with an (010) orientation for the semiconductors. We have applied thermal and material characterization (time-domain thermoreflectance (TDTR) and high-resolution transmission electron microscopy (HRTEM) together with theoretical approaches to understand the interfacial thermal transport at Al-(AlxGa1−x)2O3 and AlGa2O3 contacts. It is found that for different growth methods, the highest TBC at Al-Ga2O3 interface occurs with molecular beam epitaxy (MBE) deposition of the Al on Ga2O3. However, the experimentally measured TBC at E-beam evaporated Al interfaces is much lower than that at the MBE grown Al interfaces. The measured values are also much lower than theoretical predictions, and it is related to the interfacial chemical reactions that occur at the interfaces. The effect of Al composition on interfacial thermal transport at Al/(AlxGa1−x)2O3 interface is also studied. It is found that the TBC at the E-beam evaporated Al/(AlxGa1−x)2O3 interface is very close to that of the E-beam evaporated Al-Ga2O3 interface at different temperatures in the ternary alloy studied.

Observation of the Wurtzite Phase in OMVPE Grown ZnSe/GaAs: Effect on Implantation and Rapid Thermal Annealing

1989 ◽  
Vol 147 ◽  
Author(s):  
K. S. Jones ◽  
J. Yu ◽  
P. D. Lowen ◽  
D. Kisker
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Electrical Transport ◽  
High Resistivity ◽  
Ion Milling ◽  
Electrical Transport Properties ◽  
Wurtzite Phase ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractTransmission electron diffraction patterns of cross-sectional TEM samples of OMVPE ZnSe on GaAs indicate the existence of the hexagonal wurtzite phase in the epitaxial layers. The orientation relationship is (0002)//(111); (1120)//(220). Etching studies indicate the phase is internal not ion milling induced. The average wurtzite particle size is 80Å-120Å. Because of interplanar spacing matches it is easily overlooked. Electrical property measurements show a high resistivity (1010ω/square) which drops by four orders of magnitude upon rapid thermal annealing between 700°C and 900 °C for 3 sec. Implantation of Li and N have little effect on the electrical transport properties. The Li is shown to have a high diffusivity, a solid solubility of ≈1016/cm3 at 800°C and getters to the ZnSeA/aAs interface.

New Compounds Consisting of Turbostratic Intergrowths: Ultra-low Thermal Conductivities and Tunable Electric Properties

2011 ◽  
Vol 1329 ◽  
Author(s):  
Matt Beekman ◽  
Daniel B. Moore ◽  
Ryan Atkins ◽  
Colby Heideman ◽  
Qiyin Lin ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Scanning Transmission Electron Microscopy ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
Transmission Electron ◽  
Plane Component ◽  
Structural Space ◽  
Scanning Transmission ◽  
New Compounds ◽  
Film Form

ABSTRACTA recently discovered synthetic route to new kinetically stable [(MSe)y]m[TSe2]n layered intergrowths has been applied to prepare several different compositions (M = Pb or Sn, T = Ta, Nb, Mo, or W) with m = n = 1, in thin film form. Scanning transmission electron microscopy and synchrotron X-ray diffraction show the nanostructure of these materials is characterized by a combination of in-plane component crystallinity with misregistration and rotational mis-orientation between adjacent layers. Extremely low cross-plane thermal conductivity as low as 0.1 W m-1 K-1 are attributed to the turbostratic nanostructure. By appropriate choice of M and T, we demonstrate that a range of electrical transport properties are possible, from metallic to semiconducting. Annealing (PbSe)0.99WSe2 and (PbSe)1.00MoSe2 specimens in a controlled atmosphere of PbSe or WSe2 is observed to systematically influence carrier properties, and is interpreted in terms of reduction of the concentration of electrically active defects. Considering these observations and the large composition and structural space that can be explored in such [(MSe)y]m[TSe2]n intergrowths, these materials are of interest for further investigation as potential thermoelectric materials.

High Temperature Variable Range Hopping in Heavy Al Implanted 4H-SiC

2016 ◽  
Vol 858 ◽  
pp. 283-286 ◽  
Author(s):  
Antonella Parisini ◽  
Andrea Parisini ◽  
Marco Gorni ◽  
Roberta Nipoti
Keyword(s):  
Electrical Transport ◽  
Room Temperature ◽  
Hole Transport ◽  
Variable Range Hopping ◽  
Electrical Transport Properties ◽  
Hopping Transport ◽  
Variable Range ◽  
Transmission Electron ◽  
Temperature Variable ◽  
Post Implantation

In this work, we confirm and extend the results of a previous study where a variable range hopping transport through localized impurity states has been found to dominate the electrical transport properties of 3×1020 cm-3 and 5×1020 cm-3 Al+ implanted 4H-SiC layers after 1950-2000 °C post implantation annealing. In this study, samples with longer annealing times have been taken into account. The temperature dependence of these sample conductivity follows a variable range hopping law, consistent with a nearly two-dimensional hopping transport of non-interacting carriers that in the highest doped samples, persists up to around room temperature. This result indicates that the hole transport becomes strongly anisotropic on increasing the doping level. At the origin of this unusual electrical behavior, may be the presence of basal plane stacking faults, actually observed by transmission electron microscopy in one of the 5×1020 cm-3 samples

scholarly journals The Electrical and Thermal Transport Properties of La-Doped SrTiO3 with Sc2O3 Composite

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6279
Author(s):  
Kai Guo ◽  
Fan Yang ◽  
Tianyao Weng ◽  
Jianguo Chen ◽  
Jiye Zhang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Thermal Transport ◽  
Electrical Transport ◽  
Phonon Transport ◽  
Scattering Mechanism ◽  
Electrical Transport Properties ◽  
Thermal Transport Properties ◽  
Composite Engineering ◽  
Oxide Thermoelectric Materials ◽  
La Doped

Donor-doped strontium titanate (SrTiO3) is one of the most promising n-type oxide thermoelectric materials. Routine doping of La at Sr site can change the charge scattering mechanism, and meanwhile can significantly increase the power factor in the temperature range of 423–773 K. In addition, the introduction of Sc partially substitutes Sr, thus further increasing the electron concentration and optimizing the electrical transport properties. Moreover, the excess Sc in the form of Sc2O3 composite suppresses multifrequency phonon transport, leading to low thermal conductivity of κ = 3.78 W·m−1·K−1 at 773 K for sample Sr0.88La0.06Sc0.06TiO3 with the highest doping content. Thus, the thermoelectric performance of SrTiO3 can be significantly enhanced by synergistic optimization of electrical transport and thermal transport properties via cation doping and composite engineering.

Hollow Hemisphere Shell Formation by Pure Kirkendall Porosity

2014 ◽  
Vol 1 ◽  
pp. 61-73 ◽  
Author(s):  
Csaba Cserháti ◽  
Györgyi Glodán ◽  
Dezső L. Beke
Keyword(s):  
Void Formation ◽  
Solid State Reactions ◽  
Average Composition ◽  
Transmission Electron ◽  
Straight Line ◽  
Theoretical Predictions ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Kirkendall Porosity

Nanoshell formation has been studied experimentally in Ag/Au and Ag/Pd systems in a hemispherical geometry at different temperatures. The void formation in these systems is the result ofpureKirkendall-porosity formation, because it is caused mainly by the inequality of the intrinsic atomic fluxes and other effects (e.g. stresses), inevitably present during nanoshell formations in solid state reactions (oxides, sulphides), can be less important or can be neglected. The kinetics of the process was followed by Transmission Electron Microscopy. Both the growth and shrinkage regimes of the process were observed at the same temperature and even the temperature dependence of the characteristic time (tcr) describing the crossover of the two different regimes was observed. We succeeded to show that tcrshifts to smaller values with increasing temperature. This confirms the theoretical results:the growth and the shrinkage regimes are controlled by the faster as well as the slower diffusion coefficients (DAas well as DB), respectively. It is also illustrated that, confirming recent theoretical predictions, the pore radius linearly depends on the initial particle radius and the slope of this straight line increases with the average composition of the faster component.

scholarly journals Electrical Transport properties of Ni-Cr binary alloys

2014 ◽  
Vol 24 (2) ◽  
pp. 135
Author(s):  
P. H. Suthar ◽  
B. Y. Thakore ◽  
P. N. Gajjar
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Binary Alloys ◽  
Correlation Effect ◽  
Model Potential ◽  
Electrical Transport Properties ◽  
Wide Range ◽  
Different Temperatures ◽  
Cr Concentration ◽  
Good Agreement

Electrical transport properties viz. electrical resistivity and thermal conductivity of Ni-Cr binary alloys are determine by our recognized single parametric model potential in wide range of Cr concentration. In this work, screening functions (Ichimaru and Utsumi, Farid et al. and Sarkar et al.) are employed along with the Hartree and Taylor functions to study the relative influence of the exchange and correlation effect. Given liquid alloys are studied as a function of their composition at three different temperatures according to Faber-Ziman model. Computed values of electrical transport properties are in good agreement with the experimental data available in literature.

High-Pressure Electrical-Transport Properties of SnS: Experimental and Theoretical Approaches

2013 ◽  
Vol 117 (12) ◽  
pp. 6033-6038 ◽  
Author(s):  
Feng Ke ◽  
Jie Yang ◽  
Cailong Liu ◽  
Qinglin Wang ◽  
Yuqiang Li ◽  
...  
Keyword(s):  
High Pressure ◽  
Transport Properties ◽  
Electrical Transport ◽  
Electrical Transport Properties ◽  
Theoretical Approaches

scholarly journals The Verification of Thermoelectric Performance Obtained by High-Throughput Calculations: The Case of GeS2 Monolayer From First-Principles Calculations

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiaolian Wang ◽  
Wei Feng ◽  
Chen Shen ◽  
Zhehao Sun ◽  
Hangbo Qi ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Throughput ◽  
First Principles ◽  
Thermal Transport ◽  
Electrical Transport ◽  
Fitness Function ◽  
Industrial Applications ◽  
First Principles Calculations ◽  
Electrical Transport Properties ◽  
Thermal Transport Properties

Electronic fitness function (EFF, achieved by the electrical transport properties) as a new quantity to estimate thermoelectric (TE) performance of semiconductor crystals is usually used for screening novel TE materials. In recent years, because of the high EFF values, an increasing number of two-dimensional materials have been predicted to have the potential for TE applications via high-throughput calculations. Among them, the GeS2 monolayer has many interesting physical properties and is being used for industrial applications. Hence, in this work, we systematically investigated the TE performance, including both electronic and thermal transport properties, of the GeS2 monolayer with first-principles calculations. The results show that the structure of the GeS2 monolayer at 700 K is thermally unstable, so we study its TE performance only at 300 and 500 K. As compared with other typical TE monolayers, the GeS2 monolayer exhibits excellent electronic transport properties but a relatively high lattice thermal conductivity of 5.71 W m−1 K−1 at 500 K, and thus an unsatisfactory ZT value of 0.23. Such a low ZT value indicates that it is necessary to consider not only the electron transport properties but also the thermal transport properties to screen the thermoelectric materials with excellent performance through high-throughput calculations.

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