Schottky contacts to high-resistivity epitaxial GaAs layers for detectors of particles and X- or γ-ray photons

摘要

The electrical characteristics of Ti and Pt Schottky contacts to epitaxial n-GaAs layers with the charge-carrier concentration < 10 ~(12) cm ~(-3) for detectors of particles and X- or γ-ray photons are studied. It is shown that it is preferable to use a diffusion-based theory of charge transport in calculations of the parameters of Schottky contacts to thick high-resistivity lightly compensated GaAs layers. The calculated barrier heights were 0.84 and 0.87 eV for the Ti and Pt contacts, respectively. The fabricated samples of the surface-barrier detectors featured a linear response in the studied range of energies from 6 to 140 keV for γ-ray photons and from 4 to 8 MeV for α particles; the efficiency of charge collection was close to 100% and the energy resolution was high at room temperature.