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Surface polarity with different crystal orientations has been demonstrated as a crucial parameter in determining the physical properties and device applications in many transition metal oxide and semiconductor compound systems. The influences of surface polarity on electronic structures in nitrogen-incorporated ZnO lattices have been investigated in the present work. The successful doping of nitrogen atoms in ZnO lattices is suggested by the existence of N-related chemical bonds obtained from X-ray photoelectron spectroscopy analysis where a pronounced N–Zn peak intensity has been observed in the (000\bar 1)-terminated polar ZnO compound compared with the (10\bar 10)-terminated nonpolar ZnO compound. An energy shift of the valence band maximum towards the Fermi level has been resolved for both polar and nonpolar ZnO lattices, whereas a charge redistribution of the O 2p hybridized states is only resolved for o-plane ZnO with a polar surface. Angular-dependent X-ray absorption analyses at the O K-edge reveal enhanced surface-state contributions and asymmetric O 2p orbital occupations in the (000\bar 1)-terminated o-plane ZnO compound. The results shed light on the efficient nitrogen doping in ZnO lattices with polar surfaces. The comprehensive electronic structure investigations of correlations between impurity doping and surface polarity in ZnO lattices may also offer guidance for the material design in other transition metal oxide and semiconductor systems.

Because the traditional data encryption method remains unchanged after the key is generated, the encryption scheme is single, the encryption cost is high, and it is easy to be cracked. Aiming at the above problems, the dynamic encryption method of user privacy data based on association rules hiding is studied. Based on the DGHV encryption scheme, a dynamic encryption scheme is designed to hide the mined user privacy data association rules. After the key is processed by confounding method, the dynamic encryption process of data is completed. By comparing with the traditional methods, it is verified that the encryption efficiency of the studied method is increased by at least 26.2%, which has the advantage of low encryption cost.