Fast and safe synthesis of micron germanium in an ammonia atmosphere using Mo₂N as catalyst

Here, we reported a new method for fast and safe synthesis of a micron germanium (Ge) semiconductor. The Ge was successfully prepared from mixed GeO₂ with a low amount of MoO₃ by the NH₃ reduction method at 800 °C for an ultra-short time of 10 min. XRD patterns show that the Ge has a tetragonal structure. SEM images show that the size of the Ge particles is from 5 μm to 10 μm, and so it is on the micron scale. UV-visible diffuse reflectance spectroscopy shows that the Ge has good light absorption both in the ultraviolet and visible regions. The formation of Ge mainly goes through a two-step conversion in the NH₃ flow. Firstly, GeO₂ is converted to Ge₃N₄, and then Ge₃N₄ is decomposed to generate Ge. The comparison experiments of MoO₃ and Mo₂N demonstrate that Mo₂N is the catalyst for the Ge synthesis which improves the Ge₃N₄ decomposition. The presented fast and safe synthesis method of Ge has great potential for industrialization and the proposed Mo₂N boosting the Ge₃N₄ decomposition has provided significant guidance for other nitride decomposition systems.