GaAs detectors for underground physics

We report on the investigation of large-area GaAs Schottky diodes in view of their potential use as target detectors in the particle Dark Matter search. Rectifying contacts of different sizes have been realized with standard techniques on Si-LEC material. The I-V characteristics showed no substantial differences with respect to those of small-size diodes. Particularly, the inverse current simply scaled with the contact area regardless of the lack of any surface passivation process. To the contrary, marked differences are found in the detector response which point to a sizeable effect of the metal-semiconductor interfacial region in determining the ultimate resolution in the device.