Fast and safe synthesis of micron germanium in an ammonia atmosphere using Mo 2 N 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 GeO 2 with a low amount of MoO 3 by the NH 3 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 NH 3 flow. Firstly, GeO 2 is converted to Ge 3 N 4 , and then Ge 3 N 4 is decomposed to generate Ge. The comparison experiments of MoO 3 and Mo 2 N demonstrate that Mo 2 N is the catalyst for the Ge synthesis which improves the Ge 3 N 4 decomposition. The presented fast and safe synthesis method of Ge has great potential for industrialization and the proposed Mo 2 N boosting the Ge 3 N 4 decomposition has provided significant guidance for other nitride decomposition systems.