Metastable behavior of current-voltage characteristics in Hg1-xCdxTe p-n junctions

The n+-p junctions formed by ion implantation in p- type Hg0.6Cd0.4Te crystals are studied. It is found that leakage current of the structures at liquid nitrogen temperature is strongly dependent on the conditions during cooling from room temperature; leakage current is small after bias-off cooling and several decades higher after bias-on cooling. Both states are stable at 78 K during hours independent of bias; the reversible transitions between the states can be performed by room temperature annealing and subsequent cooling under appropriate bias. Investigations of the structures by the DLTS technique show that the variations of leakage current are accompanied by transformations of deep level spectrum of the crystal and, therefore, can be associated with the reconstruction of metastable centers located in the space charge region of the junctions. The kinetics of the metastable transitions indicates possible spreading of the transition activation energy due to local inhomogeneity of the alloy composition.