Properties of the Original Electron-Irradiated LEDs Homojunction GaP, GaAsP and Heterojunction InGaN Structures

Abstract

The work contains a detailed review of the results of research published in recent years on homojunction light-emitting diodes (LEDs) grown on the basis of GaP and GaAsP solid solution, as well as InGaN heterojunction structures with quantum wells (QWs).In order to identify the cause of the instability of the microplasma glow, it is important to analyze the electrical and spectral characteristics of the studied structures. The purpose of the study was to identify the cause that leads to the deviation from the typical dependences of I(U) and L(I) and to identify possible physical factors that underlie the occurrence of anomalies of the LEDs-radiation.The original part is based on a comparative analysis of experimental data obtained during the study of the electrophysical and spectral characteristics of both types of LEDs.The results of the study of the influence of radiation defects introduced by electrons with E = 2 MeV on the fundamental and operational parameters of the studied diodes are also presented.The increase in the differential resistance of homotransient GaP and GaAsP LEDs due to a decrease in temperature and irradiation is caused by the capture of current carriers by deep impurity levels, as well as levels of radiation defects. The value of the barrier potential of the diodes at the doses used (Fmax = 10 15 cm -2 for GaP diodes; Fmax = 2.64 cm -2 for GaAsP diodes) is practically unchanged.In InGaN heterostructure LEDs with QWs (hν = 505 nm) the NDC region begins after cooling to T ≤ 130 K; its occurrence may be related to the effect of resonant tunneling of current carriers.The short-wavelength parts of the GaP, GaAsP, and InGaN LEDs emission lines agree well with the classical Gaussian distribution; long-wavelength ones are stretched towards long-wavelengths, which is caused by the effect of the tails of the density of states (TDS) in both homo-and heterotransition structures.