Crystallization at room temperature from amorphous to trigonal selenium as a byproduct of the synthesis of water dispersible zinc selenide

Zinc selenide is a semiconductor material that has been synthesized in aqueous media. However, this synthesis can yield some byproducts, which has been little exploited in literature of this area; one of these byproducts is amorphous selenium. As this amorphous species is unable to be detected through X-ray diffraction, Raman spectroscopy plays an important role in order to track this byproduct. Additionally, the crystallization process from amorphous to trigonal selenium, due to aging at room temperature, was tracked through Raman spectroscopy and transmission electron microscopy. It was observed that, within a period of 5 months, the amorphous selenium was in great part converted to trigonal selenium, which could be deleterious to the properties of the ZnSe quantum dots.

Cubic zinc blend phase of ZnSe of 2.0 nm could be synthesized.
► Raman spectroscopy was able to detect the byproduct elemental amorphous selenium.
► Amorphous selenium crystallized at room temperature in the trigonal selenium phase.
► Raman is an essential technique for analysis of phase purity of ZnSe quantum dots.