Epitaxial structures based on compensated GaAs for gamma- 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) mum, their resistivities lie in the interval rho= (5 x 10(6)-2.5 x 10(8)) ohm cm. The thin Zn-doped p-layer has been grown upon the i-layer b y the vapour-phase epitaxy method. The electric held profiles in the p-i-n- diodes have been measured. The reverse current-voltage characteristics of t he diodes have been analysed. The sensitivity of the structures to beta- an d gamma- radiations has been investigated. (C) 2001 Published by Elsevier S cience B.V.