Nitrogen incorporation in homoepitaxial ZnO CVD epilayers

Abstract

ZnO:N thin films have been deposited on oxygen and zinc terminated polar surfaces of ZnO. The nitrogen incorporation in the epilayers, using NH3 as doping source, was investigated as a function of the growth temperature in the range between 380 °C and 580 °C. We used Raman spectroscopy and low temperature photoluminescence to investigate the doping properties. It turned out that the nitrogen incorporation strongly depends on both, the surface polarity of the epitaxial films and the applied growth temperatures. In our CVD process low growth temperatures and Zn‐terminated substrate surfaces clearly favour the nitrogen incorporation in the ZnO thin films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

“…In the present work, a clear decrease of the intensity has been observed above 400°C annealing (Figure b, inset). This is consistent with report by earlier studies on the similar system . Also, the peak positions are shifting towards the value that has been observed for N1E16 sample (Figure b) with annealing temperature above 200°C.…”

Morphological, structural and electrical investigations on non-polar a-plane ZnO epilayers

“…For compound semiconductors as for example GaN [18] GaAs [19] or ZnO [12,20] the impurity incorporation during the growth shows a strong dependency on the substrate polarity. In the case of ZnO, the O-polar c-plane surface in general favours the incorporation of group I and group III elements [12] while for example nitrogen is only incorporated in significant amount on the Zn-terminated c-plane surface [20]. A similar behaviour is known for the incorporation of Mg on the different polar surfaces of GaN [18].…”

Nitrogen and vacancy clusters in ZnO

“…8 All films were grown on nonpolar a-plane substrates since the incorporation of unintentional impurities during the CVD process is reduced by using either a-plane or c-plane Zn-face substrates as compared with O-face ZnO, 13,14 and higher nitrogen doping levels can be achieved. 7,8 Bulk ZnO samples were grown by seeded chemical vapor transport (CVT) using ammonia (NH 3 ) as a source of nitrogen dopants. 15 ZnO and graphite powder were loaded into one end of a fused silica ampoule.…”

“…One of the more promising group V dopants for obtaining p-type ZnO is nitrogen, as it should be easily incorporated on the O sublattice thanks to its similar size. Doping through both implantation [4][5][6] and incorporation during growth [7][8][9] are intensively investigated. Positron annihilation spectroscopy is an effective method for the investigation of vacancy-type defects in semiconductors.…”