Investigation of the effects of gamma radiation on the electrical properties of dilute GaAs_1-xN_x layers grown by Molecular Beam Epitaxy

This work reports the effect of gamma (γ-) irradiation on dilute GaAsN with nitrogen concentrations ranging from 0.2 to 1.2% with post-irradiation stability using Current-Voltage (I-V) and Deep Level Transient Spectroscopy (DLTS) measurements in the temperature range from 10 K to 450 K. The I-V results indicate that the irradiation effect was more pronounced in the samples with nitrogen concentration of 0.4%. Additionally, the irradiated samples showed an ideality factor higher than the as-grown samples. On the other hand, for temperatures above 265 K the barrier height of the irradiated samples with 0.8% nitrogen is higher than the as-grown samples. The DLTS measurements revealed that after irradiation the number of traps either decreased remained constant, or new traps are created depending on the concentration of nitrogen. For samples with N = 0.2% - 0.4% the number of traps after irradiation decreased, whereas for samples with N = 0.8% - 1.2 % the number of traps remained the same. However, the properties of some traps such as capture cross-sections and density increased by about 2 orders of magnitude. The origin of the defects present before and after irradiation are discussed and correlated.