Effect of Electron Irradiation on Charge Transfer in 2D Gallium Monosulfide

Abstract

The features of the effect of electron irradiation with an energy of 4 MeV and a dose of 2 × 10¹²-10¹³ cm⁻² on the dielectric properties and AC-conductivity in alternating current of a 2D layered single GaS crystal in a frequency range of 5 × 10⁴−3.5 × 10⁷ Hz are established. It is shown that the electron irradiation of a single GaS crystal increases the real component of the complex dielectric constant, decreases its imaginary component, causes the dielectric loss tangent and AC-conductivity across the layers. Both before and after the electron irradiation, the conductivity varies according to a law characteristic of the hopping mechanism of charge transfer over states localized near the Fermi level. It is shown that at 140–238 K in the layered single GaS crystals across their natural layers in the constant electric field there is also a hopping conductivity (DC-conductivity) with a variable jump length along the states localized near the Fermi level. The effect of electron irradiation on the electrical conductivity of single GaS crystals and the parameters of the states localized in their forbidden gap was studied. Taking into account the experimental data obtained in alternating and direct currents the density of states near the Fermi level and their energy spread, average hopping distances in the area of activation hopping conductivity, as well as the activation energy of jumps, are estimated in both pure and electron irradiated GaS crystals.