. Catastrophic degradation takes place in case of reaching critical values of laser radiation density power in semiconductor  lasers with  electronically pumped energy made  from  single  crystals of  some  compounds.  It has  been  accompanied by mechanical destruction of the surface at resonator ends, an irreversible decrease in radiation power and an increase in generation threshold. Moreover, during the catastrophic degradation of semiconductor lasers under the action of intrinsic radiation, significant changes in the crystal structure occur within the single crystal: dislocation density reaches a value more 1012–1015 cm–2. It has been shown that initial density of dislocations and critical power density of the intrinsic radiation are inversely proportional. Thus, the degradation process of semiconductor lasers is directly related to generation and multiplication of dislocations during laser operation. Mechanical destruction of a crystal lattice occurs at critical values of laser radiation power and dislocation density. To clarify the proposed mechanism for the degradation of semiconductor lasers, it is necessary to take into account an effect of dislocations on optical properties of semiconductors. Typically, this effect is considered as follows: dislocations cause an appearance of a local deformation field and, in addition, form space-charge regions that surround a dislocation core in the form of a charged tube. The paper proposes a model of the phenomenon under study: large stresses arise in the dislocation core, leading to a displacement of individual atoms and deformation of the crystal lattice. Lattice deformation in the dislocation core leads to a local change in the width of a forbidden band. This change value is about 10–2 eV for a screw dislocation and 10–1 eV for a boundary dislocation. The mechanism of this change is that aforementioned deformation leads to a multiple rupture of electronic bonds and an increase in the electron concentration in the dislocation core to approximately value 1018 cm–3. The developed analytical model of the degradation mechanism allows to perform selection of a semiconductor and estimation of a laser operating mode under conditions of increased radiation power.

Semiconductors are typically irradiated by low voltage electron accelerators with a continuous flow, the current density in such accelerators is 10-5-10-6 A/cm 2 , the energy-0,3-1 MeV. All changes in the properties after such irradiation are resistant at room temperature, and marked properties recovery to baseline values is observed only after prolonged heating of the crystals to a high temperature. In contrast, the authors in their studies observe an improvement of the structural properties of semiconductor crystals (annealing of defects) under irradiation with powerful (high current) pulsed electron beams of high energy (E 0 = 0,3-1 MeV, t = 0,1-10 ns, Ω = 1-10 Hz, j = 20-300 A/cm 2). In their previous paper, the authors presented theoretical basis of this effect. This article describes an experimental study on the influence of high-current pulsed electron beams on the optical homogeneity of semiconductor GaAs and CdS crystals, confirming the theory put forward earlier.

During irradiation of semiconductor crystals with powerful (high current) pulsed high-energy electron beams, a new type of annealing has been obtained. We could obtain new results and to find out physical nature of this phenomenon due to short and powerful bunches of electrons with high energy. Given its theoretical justification, the new annealing type has been called the "ionization annealing".

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