Dear colleague,

the first choice to decide whether amorphous or crystalline phase is present is x-ray diffraction due the appearence of strongs peaks or spots in case of the crystalline state. In case of amorphous state only a very broad peak shows up in the diffractogram or a halo-like spot at a film/2D-detector.

A second approach is found in EXAFS which is also sensitive to the amorphous / crystalline state via the lack of (or at least strongly reduced) 2nd and higher coordination shells contributions to the fine structure in case of the amorphous state.

You may also have a look at the following link dealing with structure determination by small angle scattering:

Article Structure of amorphous semiconductors by small angle scattering

Some semiconductor nanowires can be prepared with non-crystalline structure specially when the temperature of growth is low. However, XRD is suitable method to confirm the crystallinity of materials. In addiation, for some types of nanowires such as silicon nanowires, Raman shift could be used for knowing the wires are crystalline or amorphous by calculation Raman peak shift value that located at around 520 cm-1 for c-Si and at 480 cm-1 for amorphous. Further, you can determine the particles size depending on the shift value of Raman peak.

Regards