Electronic and optical properties – As and As+Sb doped ZnO grown by PA-MBE
|Ewa Przezdziecka 1, Marcin Stachowicz 1, Rafał Jakieła 1, Elżbieta Guziewicz 1, Jacek M. Sajkowski 1, Anna Reszka 1, Aleksandra Wierzbicka 1, Anna Droba 1, Krzysztof Kopalko 1, Adam Barcz 1, A Kozanecki 1, Wojciech Lisowski 2, Janusz W. Sobczak 2, Mirosław Krawczyk 2, Aleksander Jabłoński 2|
1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
Zinc oxide with its Eg=3.37 eV room temperature energy gap and large exciton binding energy is a prospective material for a number of applications such as ultraviolet light emitters and detectors. For applications in optoelectronic devices p-type doping of ZnO is necessary. However, this it is a difficult task due to the background n-type doping associated with high hydrogen (H) level, O vacancies (Vo) or Zn interstitials (Zni), compensating p-dopants. For obtaining p-type ZnO V group elements such as As and Sb are often used. Understanding of how As and Sb build in to ZnO matrix is valid for p-type doping.
The ZnO:As and ZnO:(As+Sb) were grown by PA-MBE method on GaN templates. The concentration of As and Sb atoms ware relatively high ~1*1020 at/cm3. The quality of the samples was examined by PL, AFM, CL, SEM and X-ray photoelectron spectroscopy (XPS). The XPS measurements showed that the As3d core level in the obtained ZnO:As films consists of two components located at 40 eV and at 43.7 eV below the Fermi level. It was found that intensity of the As3d component at binding energy of 43.7 eV is correlated with appearance of the acceptor line free electrons to acceptor FA observed in low temperature photoluminescence. This observation strongly supports the previously postulated assumption that the origin of the 43.7 eV component of the Ad3d spectra derive from arsenic atoms in AsZn-2VZn complexes. In the case of dual doped ZnO:As+Sb both As3d and Sb3d bands with binding energy 44.2 eV and 539.5 eV was observed. The binding energy of Sb3d suggests location of Sb atoms at Zn site (SbZn). Additionally, the valence band shift towards the Fermi level and As3d shift in the ZnO:As+Sb film was also observed.
Acknowledgements. The work was supported by the European Union within the European Regional Development Fund, through the Innovative Economy grant (POIG.01.01.02-00-008/08)
Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 3, by Ewa Przezdziecka
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-03-27 12:20 Revised: 2013-03-27 12:20