Aleksandr Mychko

Exciton quantum confinement in nanocones formed on a surface of CdZnTe solid solution by laser radiation

The investigation of surface morphology using atomic force microscope has shown self-organizing of the nanocones on the surface of CdZnTe crystal after irradiation by strongly absorbed Nd:YAG laser irradiation at an intensity of 12.0 MW/cm2. The formation of nanocones is explained by the presence of a thermogradient effect in the semiconductor. The appearance of a new exciton band has been observed after irradiation by the laser which is explained by the exciton quantum confinement effect in nanocones.

Increased radiation hardness of CdZnTe by laser radiation

The aim of this work is to study the possibility to increase the radiation hardness of Cd0.9Zn0.1 Te crystal using laser radiation. Pulsed Nd:YAG laser for this aim was used. Estimation of the crystalline lattice defects before and after irradiation by γ-ray using photoluminescence method in the experiments was applied. Experimental results showed the increase of the radiation hardness of CdZnTe crystal after irradiation by laser at intensity 1.20–1.80 MW/cm2.

Modification of band gap in surface layer in Cd1-xZnxTe by YAG: Nd+3 laser radiation

A mechanism of formation of graded band-gap based on Thermogradient Effect (TGE) is proposed in Cd1-xZnxTe at irradiation by second harmonic of a Q-switched YAG:Nd laser. According to the effect, the interstitial atoms of Cd (Cdi) in Cd1-xZnxTe move along the temperature gradient while the Cd vacancies (VCd) and Zn atoms - in the opposite direction, into the bulk of the semiconductor where temperature is lower. Photoluminescence (PL) spectra studied at 5 K show that concentration of Zn atoms increases due to aggregation of VCd with Zn after laser irradiation. Formation of a graded band-gap in Cd1-xZnxTe crystal at irradiation by second harmonica of YAG:Nd laser by is shown to be possible.