Characterisation of irradiation-induced defects in ZnO single crystals

The International Workshop on Positron Studies of Defects 2014

Prochazka, I.^1 ; Cizek, J.^1 ; Lukac, F.^1 ; Melikhova, O.^1 ; Valenta, J.^1 ; Havranek, V.^2 ; Anwand, W.^3 ; Skuratov, V.A.^4 ; Strukova, T.S.^4

Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, Praha 8

CZ-180 00, Czech Republic^1

Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Husinec-Rez

CZ-250 68, Czech Republic^2

Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, Dresden

01328, Germany^3

Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna

Moscow region

141 980, Russia^4

关键词: Ab initio theoretical calculations;    Irradiation-induced defects;    Optical spectroscopy;    Photoluminescence measurements;    Positron annihilation spectroscopy (PAS);    Single components;    Slow positron implantation spectroscopies;    ZnO single crystals;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/674/1/012014/pdf
DOI  :  10.1088/1742-6596/674/1/012014

来源: IOP

【 摘 要 】

Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe26+ions to fluences ranged from 3x1012to 1x1014cm-2. The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments.