No abstract

No abstract

The influence of the surface electric field on the edge photoconductivity (PC) in undoped and ytterbium-doped (N[Formula: see text][Formula: see text] 10[Formula: see text] cm[Formula: see text]) layered GaS crystals at T = 77 K irradiated with gamma quanta was investigated. It was found that the PC of layered crystals in the absorption edge region due to charge exchange of surface levels is formed as a result of electric smoothing of fluctuations in the potential of surface energy bands. The degree of smoothing of the surface bending of the zones depends on the dose of [Formula: see text]-irradiation, the concentration of impurity atoms and also on the magnitude and direction of the transverse electric field.

For the first time, information on the surface relief of the layered GaS and doped GaS:Yb single crystals subjected to gamma-irradiation was obtained using atomic force microscopy (AFM) and Fourier-transform infrared spectroscopy (FTIR). It was found that GaS is characterized by a non-uniform distribution of irregularities with different heights and periodicities, and when doping crystals with Yb atoms, the distribution of irregularities becomes more orderly, the height and periodicity of irregularities decreases. In the FTIR spectra, changes in the reflection coefficients of the surface of GaS and GaS:Yb single crystals are observed as a function of the gamma-irradiation dose (Фγ = 30…200 krad), and on the basis of spectroscopic and microscopic changes, it was found that doped single crystals are the most radiation-resistant.