GaAs Schottky versus p/i/n diodes for pixellated X-ray detectors

We discuss the performances of GaAs p/i/n structures and Schottky barriers for application as photodetectors for high-energy photons. We compare the magnitude of the leakage current and the width of the depleted region for a given reverse bias. We mention the effect of states present at the metal–semiconductor interface on the extension of the space charge region in Schottky barriers. We illustrate this effect by a description of the capacitance behaviour of a Au-GaAs barrier under γ irradiation.