| Zinc oxide (ZnO) is an important wide-band (3.37eV) semiconductor with low dielectric constant. This direct band-gap material has a large exciton binding energy (60meV), which permits excitonic recombination even at room temperature. Thus ZnO is attracting much attention as promising candidates for optoelectric applications in visible and ultraviolet regions.In low-dimension structure, the exciton binding energy will be lager than bulk material because of quantum effects, so excitons play an important role in optical characteristics of low-dimension ZnO. It's common to simplify the system as a two-dimension or a one-dimension system for exciton research in low-dimension system. However, it's hard to get the exciton wave functions. Luckily, an anisotropy system can be treated as an isotropy system in fractional-dimension space, where the dimension is determined by degree of anisotropy. As a result of that, the exciton wave function, bound-state energies, and optical spectra are obtained as a function of spatial dimensionality by solving the simple hydrogenic Schrodinger equation in the fractional-dimensional space. Moreover, this model enables one to study excitations continuously from 1~3 dimension and provide a quantitative measure of the anisotropy of interactions, as viewed from the excitation dynamics.In the paper, by fractional-dimension space model, the relationships between system dimensions and wells width in ZnO/MgZnO quantum well will be studied and the exciton dynamics such as wave functions, radial intensity and Bohr radius in ZnO/MgZnO with different well width are studied firstly. Secondly, the system dimension, exciton wave functions and absorption spectrum in hexagonal microtube ZnO film were calculated and simulated, and the confinement of microtube is discussed.Then the hexagonal microtube ZnO films are investigated by Capacitance-Voltage (C-V) Measurements and the structure of ZnO/Si were analyzed and modeled. The small-signal equivalent... |
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