Abstract
The resistivity against dose curve in neutron irradiated gallium arsenide shows an anomaly. At doses in excess of 1017 n cm-2 the resistivity decreases with dose. The temperature dependence of resistivity indicates that the mechanism of conduction at high doses is tunnel assisted hopping. Since the structural studies reveal that even at the highest dose the material remains substantially crystalline the tunnel assisted hopping is considered to occur via defect energy levels.