Влияние нейтронного облучения на спектр дефектов с глубокими уровнями в GaAs, изготовленном методом жидкофазной эпитаксии в атмосфере водорода и аргона

The results of experimental studies of capacitance– voltage characteristics, spectra of deep-level transient spectroscopy of graded high-voltage GaAs p+−p0−i−n0 diodes fabricated by liquid-phase epitaxy at a crystallization temperature of 900C from one solution–melt due to autodoping with background impurities, in a hydrogen or argon ambient, before and after irradiation with neutrons. After neutron irradiation, deep-level transient spectroscopy spectra revealed wide zones of defect clusters with acceptor-like negatively charged traps in the n0-layer, which arise as a result of electron emission from states located above the middle of the band gap. It was found that the differences in capacitance–voltage characteristics of the structures grown in hydrogen or argon ambient after irradiation are due to different doses of irradiation of GaAs p+−p0−i−n0 structures and different degrees of compensation of shallow donor impurities by deep traps in the layers.

Engineering defect clusters in distorted NaMgF3 perovskite and their important roles in tuning the emission characteristics of Eu3+ dopant ion

Defect engineering in distorted NaMgF3 can be achieved by doping different amounts of dopant (Eu3+) and co-dopant (Li+) ions, which has a significant impact on the emission spectrum and photoluminescence decay profile of the Eu3+ ion.

Экспериментальные исследования модификации характеристик GaAs-структур с контактами Шоттки после воздействия быстрых нейтронов

The electrophysical parameters and surface morphology of GaAs n/n- structures with Schottky contacts before and after neuron impact with an average energy of about 1 MeV were studied. Changes in the profiles of the concentration and mobility of electrons in the structures were determined by the C-V method measurements. The method of atomic force microscopy helped to find radiation defect clusters which appearing during impact. A complex approach to the determination of their parameters is proposed.

Effect of Sequential Helium and Nickel Ion Implantation on the Nano-Indentation Hardness of X750 Alloy

Sequential He+ and Ni+ implantations were performed to investigate their combined effect on the indentation hardness of heat-treated Inconel X750 alloy. The microstructure of the ion-implanted region was also characterized with TEM. The alloy displayed a pronounced softening with very low Ni+ implantation levels, ? = 0.01 - 1.0 dpa, however it showed a clear increase in hardness when implanted with He+ up to CHe = 5000 appm. Samples subjected to sequential He+ and Ni+ implantations displayed hardness values between those presented by sole He+ or Ni+ implantation suggesting that the effects of ion-induced microstructural damage and helium accumulation on the hardness of this alloy can be considered as independent and additive over the range of conditions studied. This observation is in contradiction to previously reported TEM studies which suggest that accumulated helium slows the dissolution/disordering of the ?' hardening phase in this alloy. In our study, established theories were applied to assess the contribution of ion-induced defect clustering, ?' precipitate disordering, and helium bubble accumulation to the hardness of the X750 alloy. It was observed that generation of ion-induced defect clusters and the formation of helium bubbles increased the indentation hardness slightly while the disordering of ?' precipitates resulted in a dramatic decrease in the total hardness. Ni+ and He+ implantation also had different effects on the depth dependence of the indentation hardness (ISE). ISE was pronounced in the samples subjected to Ni+ implantation while it was almost absent in samples subjected to He+.