Nitrogen-doped ZnO shells: Studies on optical transparency and electrical conductivity

Studies on optical and electrical conductivity in nitrogen (N)-doped ZnO shells are explored. On incorporating low levels of nitrogen, the (0 0 2) X-ray diffraction (XRD) peak was found to be intensified significantly. Closely packed spherical crystallites of ZnO were transformed into flat-flakes during 0.1-0.3 M nitrogen doping and finally to shells, flattered at the center and tapered at ends, at 0.4 M. Both pristine and N-doped ZnO films show hydrophilic character. It was also found that the degree of transparency and the nature of conductivity as estimated by optical absorbance and Hall measurement, respectively, were strongly influenced by the levels of N-doping. Higher nitrogen doping led to decline in electrical resistivity and mobility due to an enhancement of free charge carriers. Presence of both (N-2)o donor and (N)0 acceptor peaks in X-ray photoelectron spectroscopy could be responsible for the formation of higher carrier concentration in ZnO films. (C) 2012 Elsevier Ltd. All rights reserved.Financial support from the agencies: (a) Hydrogen Energy R & D Center, one of the 21st century frontiers in R & D program funded by Ministry of Science and Technology of Korea and (b) the Technology Innovation Program (or Industrial Strategic Technology Development Program, K00060-601) funded by the Ministry of Knowledge Economy (MKE, Korea) is greatly acknowledged