Ammonothermal synthesis of thick gallium nitride film employing acidic mineralizers

Dirk Ehrentraut, Yuji Kagamitani, Akira Yoshikawa, Naruhiro Hoshino, Hirohisa Itoh, Shinichiro Kawabata, Katsushi Fujii, Takafumi Yao, Tsuguo Fukuda

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Fabrication of wurtzite-type gallium nitride (GaN) thick films on HPVE-grown {0001} GaN substrates under moderate ammonothermal conditions is reported. Supercritical ammonia (NH3) as solvent and the mineralizer ammonium chloride (NH4Cl) is employed for temperature and pressure conditions of 400-550 °C and ≥ 135 MPa, respectively. Growth rates of 30 μm per day over long-term growth runs were obtained. The effect of surface morphology of the substrate on homoepitaxial nucleation of GaN films prepared from ammonoacid solutions is investigated. Two-dimensional nucleation is obtained for substrates etched by hot concentrated KOH prior film growth. In this case the interface between film and the (0001̄) substrate does not show any signs of voids or island nucleation. Cracking pattern reveals similar mechanical-elastical properties for film and substrate.

Original languageEnglish
Pages (from-to)2270-2275
Number of pages6
JournalJournal of Materials Science
Issue number7
Publication statusPublished - 2008 Apr

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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