Fabrication and characteristics of a fully depleted semi-insulating GaAs semiconductor detector for alpha radiation detection at room temperature in air

Abstract

Fully depleted GaAs Schottky barrier detectors were fabricated by using a semi-insulating (SI) bulk crystal with a thickness of 350 mu m and an orientation of (100). The bulk SI-GaAs detector structure was Au/Ti-GaAs-Ni/Au. The leakage current density responses to the bias voltage were used to determine the Schottky barrier height (SBH). The determined SBHs were placed in the range of 0.80 - 0.83 eV for metal work functions from 4.3 to 5.2 eV on the basis of the thermo-ionic emission theory. Alpha particle resolution was determined by using a 5.5-MeV Pu-238 source at room temperature in air at a 1-atm pressure. As a result, the bulk SI-GaAs detectors showed a moderate response to alpha particle; thus, they are promising candidates for an alpha particle detector at room temperature in air.