2007 Fiscal Year Final Research Report Summary
Single crystal growth of group III nitride semiconductors by slow cooling of their melts under high pressure
| Project/Area Number |
17360013
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
UTSUMI Wataru Japan Atomic Energy Agency, Quantum Beam Science Directorate, Principal Researcher (60193918)
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| Co-Investigator(Kenkyū-buntansha) |
SAITOH Hiroyuki Japan Atomic Energy Agency, 量子ビーム応用研究部門, Senior Post-Doctoral Fellow (20373243)
HATTORI Takanori Japan Atomic Energy Agency, 量子ビーム応用研究部門, Researcher (10327687)
KANEKO Hiroshi Japan Atomic Energy Agency, 量子ビーム応用研究部門, Collaborating Engineer (20425565)
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| Project Period (FY) |
2005 – 2007
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| Keywords | nitride semiconductors / allium nitride / indium nitride / high pressure / high temperature / single crystal |
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| Research Abstract |
The aim of this project is to investigate the crystal growth of various group-In nitride semiconductors under high pressure conditions. As the first stage, we built a new high pressure/temperature apparatus with a 1500 ton hydraulic press. Many technical developments have been made: the P-T conditions required for the GaN single crystal growth (>6GPa and>2200℃) was successfully generated and pyrollitic BN was found to be a good container under such severe conditions.
Intensive studies on InN have been made. Its P-T phase diagram was determined up to 20GPa and 2000℃ by in situ diffraction with synchrotron radiation, which showed that wurtzite-rocksalt phase boundary was located around 10 GPa, and InN decomposed into In and N_2 in the wurtzite phase regions. Melting of InN was not observed in the P-T region investigated and thus the possibility of single-crystal growth from the melt that occurred in GaN is ruled out for InN. The decomposition P-T relation experimentally obtained was used to calculate the standard enthalpy of formation of InN at ambient conditions as -36.3 M/mol and to estimate. the decomposition temperature at 1 bar as 204K Experiments on In_2O_3 have also been carried out and we were successful for recovering a single crystal of high pressure phase of In203 that has rhombohedral corundum structure. Furthermore, our high pressure/temperature project has provided an unexpected result related to the bulk metallic glass; formations of bulk metallic glass of elemental Zr sensationally reported by US group was contradicted with our precise experiments.
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