Epitaxial gallium arsenide for nuclear radiation detector applications

Radiation detectors consisting of MBE-, LPE-, and MOCVD-grown gallium arsenide layers were fabricated by employing standard photolithography techniques. The active region of the devices varied between 5 and 60 mu m thickness. Hall and CV measurements confirm the high quality of the material with unintended residual doping densities of the order 10(14)/cm(3) and mobilities typical for GaAs. Dark current densities as low as j(D) = 0.2..2.0 mu A/cm(2) were achieved for all devices. The energy resolution (FWHM) at room temperature for 60 keV gamma-photons was 1.8 keV, while for 5.8 MeV alpha-particles (Cm-244) energy resolution of 18.3 keV (FWHM) has been determined. The detectors exhibit a charge collection efficiency of approximately 100% within the experimental error.