Laser-induced structure defects and their use for modification of properties of (Cd,Hg)Te epitaxial layers and CdTe crystals

摘要

This Paper examines the experimental researches of structural defect generation in (Cd,Hg)Te epitaxil layers on CdTe substrates and CdTe mono-crystals after pulse laser treatment and the influence of these defects on mechanical, optical and galvano-magnetic properties of the samples. In the experiments we used the ruby laser radiation with energy density changed in the range 1,5-15 J/cm~2. The duration of laser pulses (τ) was about 1,5 ms. Changes in the chemical composition of the irradiated surface have been analyzed by the Auger electron spectroscopy. The zones with increased defect concentration were determined by the method of the selective chemical etching. It has been determined that the pulse laser processing results in both the essential redistribution of the component concentration and generation of the point and extended defects in near-surface crystal layers excited by laser irradiation. After the laser irradiation of the samples the redistribution of the intensity of the luminescence bands and emergence of a new band were observed over the band 840 nm at the temperature of samples about 4,2 K. The essential growth of the spectral band intensity with a maximum within the band 875-885 nmat T= 77 K has been observed as well.