Alternative precursors for MOVPE growth of InN and GaN at low temperature

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We report on the use of dimethylhydrazine (DMHy) and tertiarybuthylhydrazine (TBHy), as alternative nitrogen precursor for GaN low-temperature growth, as well as to improve the InN growth rate. Lowering the GaN growth temperature, would allow growing InN/GaN heterostructures by MOVPE, without damaging the InN layers. Increasing the low InN MOVPE growth rate is of major importance to grow reasonably thick InN layers. In this respect, triethylindium (TEIn) was also used as an alternative to trimethylindium (TMIn). We demonstrate that tertiarybutylhydrazine is a suitable nitrogen source for GaN growth at 600 °C, leading to crystalline GaN layers. These layers exhibited a peak of photoluminescence emission at 3.475 eV, at 2 K, with a narrow linewidth of 18 meV; while no detectable photoluminescence was observed for layers grown with ammonia. This result opens the way to further MOVPE growth of InN and GaN based heterostructures. The unsuccessful GaN growth in a nitrogen or argon ambient using DMHy, in contrast with hydrogen, demonstrates the active role of hydrogen in the growth process. Both DMHy and TBHy were unsuitable to grow InN, but the use of TEIn instead of TMIn together with ammonia resulted at least in doubling the InN growth rate in same growth conditions.