Epitaxial structures based on compensated GaAs for γ- and X-ray detectors

The growth and characteristics of the detector p–i–n-structures fabricated by means of the epitaxial methods are discussed. High-resistivity i-layers containing chromium as a compensated impurity have been grown on the n-GaAs substrates by the liquid-phase epitaxy method. The layer thicknesses are (150–250) μm, their resistivities lie in the interval ρ=(5×106–2.5×108) ohm cm. The thin Zn-doped p-layer has been grown upon the i-layer by the vapour-phase epitaxy method. The electric field profiles in the p–i–n-diodes have been measured. The reverse current-voltage characteristics of the diodes have been analysed. The sensitivity of the structures to β- and γ- radiations has been investigated.