Application of epitaxial GaAs to medical imaging

We show that GaAs is a promising material for X-ray medical imaging detectors. Indeed, fluorescence degrades the spatial resolution, and GaAs optimises the compromise between absorption and spatial resolution. We describe the performances (spatial resolution, linearity, energy resolution and temporal response) reached by detectors made of the thick epitaxial GaAs layers we produce, in order to illustrate that such detectors qualify for medical imaging. Finally the main limitation, related to the level of residual doping in an epitaxial layer, is discussed.