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In this study, the Mg doping effects on the nanostructural dependence of photoluminescence and the photosensing properties in Zn1−xMgxO (x = 0.01, 0.03, and 0.05) nanorod arrays were systematically examined. The vertical-aligned nanorod arrays were separately grown on ZnO-seeded n-Si substrates via a low-temperature hydrothermal process. X-ray diffraction analysis revealed that all Zn1−xMgxO nanorod arrays exhibited the same preferentially c-oriented wurtzite structure. Images of all the Zn1−xMgxO nanorod arrays provided by field emission scanning electron microscope showed that both the length and diameter of the Zn1−xMgxO nanorod arrays increased with increasing Mg doping concentration. Also, an enhanced blue-shifted ultraviolet (UV) emission and a reduced visible emission were observed from the photoluminescence spectra of the Zn1−xMgxO nanorod arrays. The former indicated the decrease of defects and the latter indicated the enhancement of the crystallinity and the increase in optical bandgap. Current–voltage curves were separately measured in the dark and under UV illumination. Finally, the mechanism of the Mg doping effects on the corresponding defects, bandgap, and UV photosensing characteristics of the Zn1−xMgxO nanorod arrays was investigated in detail.

Modelling of thermal deformation and the corresponding stress distribution are significant for the thin-film design. In order to evaluate the mechanical properties experienced by a thin film parameter on the rigid substrate, the author proposes a semi-analytical model to estimate the deformation of the thin film under various conditions. The physical interpretation and simplification of each term is obtained through the order-of-magnitude analysis. Analytical forms for the thin film deformation can be obtained, and the stress in the film can be easily determined using the proposed model through the constitutive law.

Praseodymium-substituted bismuth titanate (Bi 3.2 Pr 0.8 Ti 3 O 12 , BPTO) thin films were successfully deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by spin coating with a sol-gel technology and rapid thermal annealing. The effects of annealing atmospheres (vacuum, ambient atmosphere and oxygen) on the growth and properties of thin films were investigated. The results show that the intensity of the (117) diffraction peak of Bi 3.2 Pr 0.8 Ti 3 O 12 film annealed in oxygen is stronger than those annealed in ambient atmosphere and vacuum. The XRD spectra demonstrated that a highly (117) orientation could be obtained when the Bi 3.2 Pr 0.8 Ti 3 O 12 thin film was annealed in an oxygen-sufficient environment. The BPTO thin films annealed in oxygen atmosphere exhibits the maximum remanent polarization (2P r ) of 49 μC/cm 2 and a low coercive field (2E c ) of 130 kV/cm, fatigue free characteristics up to ≥10 11 switching cycles. These results indicate that the BPTO thin film is useful in nonvolatile ferroelectric random access memory applications.