Podolian A. Influence of ultrasound on defects and photoelectrical phenomena of silicon and silicon based structures

Thesis is devoted to experimental studies of photoelectric phenomena in silicon monocrystals and silicon based nanostructures affected by the defect generation, redistribution and annealing in the presence of ultrasound. The cold annealing of point radiation defects produced by g-irradiation 60Co is demonstrated for the first time. This effect is found to be not, due to the known thermal annealing of the defects in silicon. Tentative models explaining the effect are discussed as being due to the E-center annealing in float-zone-grown silicon and the C-O-V2 complex in Czochralski-grown silicon. It is shown that the E-center annealing effect can be used to restore the performance of nuclear detectors degradated by the influence of the radiation. The crystal volume purification from harmful K and Na dopants, and electrically-active radiation defect non-uniformity distribution decrease are both achieved by using ultrasonic loads.It is also shown that simultaneous treatment of SixGe1-x layers by to He+-ionbombardment and ultrasound action is capable of decreasing the threading dislocation concentration produced by the thermal relaxation of SixGe1-x/Si structures. The spectral changes of the photovoltage in Au/SixGe1-x/Si structures and photoluminescence in porous silicon in the presence of ultrasound loads are found to be due to the redistribution of structural defects in acoustic fields.