DEEP LEVELS IN P-N-STRUCTURES BASED ON GaAsP

Abstract

Research of deep levels in p-n-structures based on a GaAsP solid solution has been done. It is shown that a significant spread in the efficiency of the studied LEDs is due to the difference in the composition of GaAsP in the active region. It has been determined that the main parameter that determines the efficiency of a light-emitting diode is its internal quantum efficiency, which is associated with the probability of radiative and nonradiative transitions. It is connected with deep levels caused by various types of defects. The ionization energies of deep levels in the depletion layer of p-n-junctions are determined using the method of thermally stimulated currents (TSC). It is shown that the presence of such levels can lead to a significant increase in the series resistance of the LED, which in turn will lead to a decrease in efficiency and additional heating of the diode. The structure and parameters the samples that investigated are described. Information about distribution of impurities in p-n-junctions of light-emitting diodes based on GaAsP was obtained by measuring the capacitance-voltage characteristics. Device that used to determine the TSС is described. The results of calculations of deep impurity levels and their concentration from the TSC curves for various LEDs based on GaAsP are presented.