Low temperature thermal conductivity of zinc oxide

Wolf, Mario; Martin, J. J.

doi:10.1002/pssa.2210170124

Cited by 43 publications

(21 citation statements)

References 10 publications

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“…(6) were determined by matching the modeling to experimental data for bulk ZnO sample. As a result, the theoretical data with A 1 = 8.0eÀ44 s 3 , B 1 = 2.6eÀ19 s/K, and B 2 = 100 K showed good agreement with experimental data [36,37] for the bulk sample as shown in Fig. 4.…”

Section: Thermal Conductivity Of Wick Layersupporting

confidence: 81%

Micromachined passive phase-change cooler for thermal management of chip-level electronics

Pisano

2015

International Journal of Heat and Mass Transfer

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a b s t r a c tThis paper reports an efficient and reliable passive cooling device using phase-change of coolant in response to the needs of chip-level electronics applications in which heat dissipation must be removed as rapidly and continuously as possible. The design of this cooling device was developed with three functional layers including evaporator, wick, and reservoir, which provided enhanced capillary forces, allowing reliable cooling performance without wick dryout and coolant back flows. Cooling performance by the developed system was demonstrated experimentally with a combination of microfabrication techniques and nanomaterial synthesis, showing rapid and efficient heat removal ability by enhanced and extended capillary action during the operation. The chronic dryout limitation in micro cooling devices could be addressed by the proposed thermal system.

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Section: Thermal Conductivity Of Wick Layersupporting

confidence: 81%

Micromachined passive phase-change cooler for thermal management of chip-level electronics

Pisano

2015

International Journal of Heat and Mass Transfer

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“…4, due to the small grain size. The thermal conductivity of ZnO is basically high due to its light constituent elements and bonding nature, and it exceeds 100 W/m K for a single crystal 9 and 30 W/m K to 40 W/m K for polycrystalline bulk prepared by conventional sintering. 10,11 Hot-pressing of nanoparticles synthesized by coprecipitation results in a reduction in thermal conductivity to 20 W/m K, 12 because grain growth during hot-pressing results in a grain size of 1 lm, although the starting material was in the nanometer range.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties of Nanograined ZnO

Kinemuchi

Mikami

Kobayashi

et al. 2009

Journal of Elec Materi

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Bulk ZnO with a grain size of 20 nm was successfully obtained by pulsed electric current sintering. The crystalline size was almost identical to that of the raw particles, because the sintering temperature was as low as 200°C. A pressure of 500 MPa effectively enhanced densification, leading to a relative density of >90% at 200°C. The small grain size led to a low thermal conductivity of 3 W/m K at room temperature, due to enhanced boundary scattering. The Seebeck coefficient was higher than that of micrograined ZnO with similar Ga doping (0.3 at.% Ga). However, the resistivity was increased by more than 1000 times. The temperature dependence of conductivity showed thermally activated conduction behavior, while that of micrograined ZnO exhibited metallic-like behavior. The thermoelectric properties suggest that a carrier trap in the nanograined ZnO hinders carrier transport. Surface modification of the ZnO nanoparticles by heat treatment in H 2 resulted in observable photoluminescence which was quenched in the starting nanoparticles, and led to a decrease in the resistivity of the sintered bulk, which indicates that control of surface defects on the nanoparticles is crucial for enhancement of the thermoelectric properties of nanograined ZnO.

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“…Figure 12 shows the thermal conductivity for nanobelts of different lateral sizes. First, we note that the values are between 3-15 W/(m·K) which is an order of magnitude lower than that for bulk ZnO (∼100 W/(m·K)) [33]. The significant difference seen here is primarily associated with the high surface-to-volume ratios of the nanobelts.…”

Section: Thermal Conductivity and Effect Of Surface Scattering Of Phomentioning

confidence: 84%

Surface-effects-dominated thermal and mechanical responses of zinc oxide nanobelts

Kulkarni

Zhou

2006

Acta Mech Mech Sinica

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Molecular dynamics (MD) simulations are carried out to characterize the mechanical and thermal responses of [0110]-oriented ZnO nanobelts with lateral dimensions of 21.22 Å × 18.95 Å, 31.02 Å × 29.42 Å and 40.81 Å × 39.89 Å over the temperature range of 300-1000 K. The Young's modulus and thermal conductivity of the nanobelts are evaluated. Significant surface effects on properties due to the highsurface-to-volume ratios of the nanobelts are observed. For the mechanical response, surface-stress-induced internal stress plays an important role. For the thermal response, surface scattering of phonons dominates. Calculations show that the Young's modulus is higher than the corresponding value for bulk ZnO and decreases by ∼33% as the lateral dimensions increase from 21.22 Å × 18.95 Å to 40.81 Å × 39.89 Å.The thermal conductivity is one order of magnitude lower than the corresponding value for bulk ZnO single crystal and decreases with wire size. Specifically, the conductivity of the 21.22 Å × 18.95 Å belt is approximately (31-18)% lower than that of the 40.81 Å × 39.89 Å belt over the temperature range analyzed. A significant dependence of properties on temperature is also observed, with the Young's modulus decreasing on average by 12% and the conductivity decreasing by 50% as temperature increases from 300 K to 1000 K.

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Low temperature thermal conductivity of zinc oxide

Cited by 43 publications

References 10 publications

Micromachined passive phase-change cooler for thermal management of chip-level electronics

Micromachined passive phase-change cooler for thermal management of chip-level electronics

Thermoelectric Properties of Nanograined ZnO

Surface-effects-dominated thermal and mechanical responses of zinc oxide nanobelts

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