Investigation of point defects in ZnO and their interaction with hydrogen and nitrogen
Complex investigations of point defects in ZnO are proposed in the present project. Positron annihilation
spectroscopy (PAS) including also variable energy PAS using slow positron beam will be used as a principal technique for defect studies. State–of–art ab-initio theoretical calculations will be employed for
interpretation of PAS data. Defects in ZnO single crystals will be compared with those in epitaxial and
nanocrystalline ZnO thin films. Defects studies will be combined with electrical (temperature-dependent
Hall effect, deep level transient spectroscopy) and optical (photoluminescence, optical transmission)
measurements in order to find a link between predominant defect configurations and specific electrical
and optical properties of ZnO samples. Moreover, in the present project we intend to investigate
interaction of hydrogen and nitrogen with point defects in ZnO and influence hydrogen and nitrogen on
electrical and optical properties. A new UHV chamber for on-line sputtering of ZnO films will be
constructed and connected to slow positron beam. This novel setup enables to perform variable energy
PAS investigations of thin ZnO films in-situ during film deposition. It gives us an exclusive possibility to
investigate formation of defects and incorporation of impurities into ZnO lattice during film growth.
