The use of X-ray absorption spectroscopy and related techniques in the investigation of the structure of amorphous group IV based semiconductor alloys is briefly reviewed, with emphasis on recent results.
In these materials the single scattering contribution to the x-ray absorption signal contains information mainly on first shell coordination; this is illustrated by showing trends in the local structure of amorphous semiconductor alloys. This type of analysis can be complemented by using other methods. For example, X-ray scattering yields information on second shell structure which reflects the influence of bond angle disorder.
Recent results on a-Si-1-xCx:H are then reported. Presence of both carbidic and graphitic carbon, interatomic distances which are constant with composition and a clear tendency towards chemical order are found. These results are compared to some recent structural models.