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New effects of modification of spectrum of radiation of light-emitting diode in magnetic field, which give the chance to use a LED as an optoelectronic magnetic field sensor, are discovered. Physical phenomena that appear in light-emitting diodes in a magnetic field are considered. Amplitudemodulated by a magnetic field the optical signal can be obtained if to use a LED with narrow base, where it is possible to gain 50 % magnification of energy of an emission light in a magnetic field. If a LED with long vary-band base is being used as magneto-sensitive element, the magnetic field will shift effective region of recombination to a section with other energy gap, and the LED’s radiated frequency will change. Thus, we obtain a frequency-modulated by a magnetic field optical signal, which is resistant to noises in optical channels. Such detectors of magnetic field are expedient for using in systems with optical processing methods of the information.

The influence of the motion of impurity centers on the stability of GaInAsP-based light- emitting diodes and their efficiency are studied. The stability and efficiency of the electroluminescence of LEDs is mainly determined by the ratio between the intensities of the radiative and non-radiative recombination of charge carriers. We studied the electroluminescent and electrical characteristics of LEDs. To clarify the degradation mechanism of LEDs, we studied the effect of their current training for 3000 hours at various current densities for stability and efficiency and for their electrical characteristics. It was shown that the degradation of LEDs at low injection levels is associated with the drift of impurity centers near the inhomogeneities of р-л-junctions. It is shown that during the degradation of LEDs, the magnitude of the radiative current component at a fixed voltage varies little. At the same time, nonradiative current components increase significantly. It was established that the growth of nonradiative current components is associated with the drift of mobile impurities to inhomogeneities of the р-л-junction. The kinetics of LED degradation was calculated using certain assumptions. The diffusion coefficient of the ions responsible for the degradation of the diodes is estimated. It is shown that “sudden” LED failures are of the same nature as their gradual degradation. They can occur at a sufficiently high concentration of mobile impurities. The obtained dependences of the radiation intensity on the duration of degradation can be used to estimate the diffusion coefficient of a mobile impurity.

Impurity sites in LEDs based on of Gai-xAlxAs for fiber-optic communication lines using thermal-stimulated current method were researched. The causes of the degradation of such diodes are clarified. The installation for research using the method of thermal-stimulated currents is described. Given in p-n junctions based on GaAlAs. The dependence curves of thermal-stimulated currents and temperature are shown at various heating rates. Was made a research of light-emitting diodes degradation by their power supply of current pulses up to 10 A, with a duration of 100 ns and a frequency of 300 Hz, as well as at 50 mA, 20 mA and a temperature of 800C. A connection was found in the process of degradation of LEDs with an increasing of the concentration of impurity sites. The curves of thermal-stimulated currents determined the concentration of impurity sites before and after the degradation of LEDs. It is shown that the main reason for the change in the electrical characteristics of the p-n junctions of the studied samples upon passing a direct current is the accumulation of impurity sites.

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