High thermal conductivity of gallium nitride (GaN) crystals grown by HVPE process

Hiroyuki Shibata, Yoshio Waseda, Hiromichi Ohta, Kazumasa Kiyomi, Kenji Shimoyama, Kenji Fujito, Hirobumi Nagaoka, Yuji Kagamitani, Rayko Simura, Tsuguo Fukuda

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123 Citations (Scopus)


A relatively large sample of gallium nitride (GaN) was grown as a single crystal using the hydride vapor phase epitaxy (HVPE) process. The thermal diffusivity of the single crystal has been measured using a vertical-type laser flash method. The thermal expansion was measured using a dilatometer in order to estimate the thermal diffusivity with sufficient reliability. The effect of sample thickness and temperature on thermal diffusivity was evaluated. The specific heat capacity of GaN was also measured by using a differential scanning calorimeter. The thermal properties of single-crystal GaN have been compared with the measured thermal properties of single-crystal silicon carbide (SiC), The thermal conductivity of single-crystal GaN at room temperature is found to be 253 ± 8.8% W/mK, which is approximately 60% of the value obtained for SiC. The excellent thermal property that is obtained in this study clearly indicates that GaN crystals are one of the promising materials for use in high-power-switching devices.

Original languageEnglish
Pages (from-to)2782-2786
Number of pages5
JournalMaterials Transactions
Issue number10
Publication statusPublished - 2007 Oct


  • Gallium nitride
  • Laser flash method
  • Thermal conductivity
  • Thermal diffusivity
  • Thermal expansion


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