Point defects in ZnO crystals grown by various techniques
In the present work point defects in ZnO
crystals were characterized by positron lifetime spectroscopy combined with
back-diffusion measurement of slow positrons. Defects in ZnO crystals grown by
various techniques were compared. Hydrothermally grown ZnO crystals contain
defects characterized by lifetime of ≈181 ps. These defects were attributed to Zn vacancies
associated with hydrogen. ZnO crystals prepared by other techniques (Bridgman,
pressurized melt growth, and seeded chemical vapour transport) exhibit shorter
lifetime of ≈165
ps. Positron back-diffusion studies revealed that hydrothermally grown ZnO
crystals contain higher density of defects than the crystals grown by other
techniques. The lowest concentration of defects was detected in the crystal grown
by seeded chemical vapor transport.
Source:IOPscience
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