© 2018, National Institute of Optoelectronics. All rights reserved.The electrical characteristics of a double type II heterojunction in the GaSb/GaInAsSb/GaSb system with stagger ed band alignment were studied. The dark current mechanisms in the heterostructures were investigated at several temperatures. The experimental results shows that, the low temperature region the tunneling mechanism(⋎ of the current flow dominates in both, forward and reverse biases. Have been investigated the radiation effect of60Co)-ray source with 6 MeV photon energy and 1.5x1011 gamma/cm2 fluency on the electrical and optical characteristics.