Transport properties, specific heat and thermal conductivity of GaN nanocrystalline ceramic

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.07.052· OSTI ID:21421501

Sulkowski, Czeslaw ^[1]; ChuchmaLa, Andrzej ^[2]; Zaleski, Andrzej J; Matusiak, Marcin; Mucha, Jan; GLuchowski, PaweL; Strek, WiesLaw ^[1]

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1. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)
2. Wroclaw University of Technology, Institute of Electrical Engineering Fundamentals (I7), Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

The structural and transport properties (resistivity, thermopower and Hall effect), specific heat and thermal conductivity have been measured for GaN nanocrystalline ceramic prepared by hot pressing. It was found that the temperature dependence of resistivity in temperature range 10-300 K shows the very low activation energy, which is ascribed to the shallow donor doping originating in amorphous phase of sample. The major charge carriers are electrons, what is indicated by negative sign of Hall constant and Seebeck coefficient. The thermopower attains large values (-58 {mu}V/K at 300 K) and was characterized by linear temperature dependence which suggests the diffusion as a major contribution to Seebeck effect. The high electron concentration of 1.3x10{sup 19} cm{sup -3} and high electronic specific heat coefficient determined to be 2.4 mJ/molK{sup 2} allow to conclude that GaN ceramic demonstrates the semimetallic-like behavior accompanied by very small mobility of electrons ({approx}0.1 cm{sup 2}/V s) which is responsible for its high resistivity. A low heat conductivity of GaN ceramics is associated with partial amorphous phase of GaN grains due to high pressure sintering. - Graphical Abstract: Thermal resistivity and thermopower measurements indicates the high phonon scattering and lack of phonon-drag contribution to thermopower in GaN nanoceramics pressed under 4 GPa at 800 {sup o}C.

• OSTI ID: 21421501
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 10; Other Information: DOI: 10.1016/j.jssc.2010.07.052; PII: S0022-4596(10)00337-3; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
AMORPHOUS STATE
CERAMICS
CRYSTALS
ELECTRONIC SPECIFIC HEAT
GALLIUM NITRIDES
HALL EFFECT
HEAT
HOT PRESSING
NANOSTRUCTURES
PRESSURE RANGE GIGA PA
SEEBECK EFFECT
SINTERING
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THERMAL CONDUCTIVITY
ENERGY
FABRICATION
GALLIUM COMPOUNDS
MATERIALS WORKING
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
PRESSING
PRESSURE RANGE
SPECIFIC HEAT
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES