We have investigated the electronic structures ofn- orp-type doped ZnO based onab initioelectronic band structure calculations. We findunipolarityin ZnO;n-type doping using Al, Ga or In species decreases the Madelung energy whilep-type doping using N species increases the Madelung energy, in addition to causing substantial localization of the N states. Codoping using reactive codopants, Al, Ga or In, enhances the incorporation of N acceptors inp-type codoped ZnO. We find the delocalized states of N forp-type ZnO codoped with N and Al (Ga).

Transparent conducting polycrystalline Ga-doped ZnO (GZO) films with different thicknesses were deposited on glass substrates at a substrate temperature of $200°\text{C}$ by ion-plating deposition with direct current arc-discharge. The dependences of crystal structure, electrical, and optical properties of the GZO films on thickness have been systematically studied. Optical response due to free electrons of the GZO films was characterized in the photon energy range from 0.73 to 3.8 eV by spectroscopic ellipsometry (SE). The free electron response was expressed by the simple Drude model combined with the Tauc–Lorentz model. From the SE analysis and the results of Hall measurements, electron effective mass, $m^{\ast }$ , and optical mobility, ${\mu }_{\text{opt}}$ , of the GZO films were determined, based on the assumptions that the films are homogeneous and optically isotropic. By comparing the ${\mu }_{\text{opt}}$ and Hall mobility, ${\mu }_{\text{Hall}}$ , an indication on the effect of ingrain and grain boundary scattering limiting the electron mobility has been obtained. Moreover, the variation in scattering mechanism causing thickness dependence of ${\mu }_{\text{Hall}}$ was correlated with the development of polycrystalline grain structure.

We present evidence of the focusing effects of fine glass capillary optics for MeV He ion beams. The glass capillary optics are formed by a puller as to have inlet diameters of about 1 mm and outlet diameters of submicrons. The total length of the optics is about 50 mm. Impingent MeV ions to such optics are reflected by the inner wall several times, in a very similar process to the so-called surface channeling. The majority of incident ions are lost by the dechanneling, or large-angle scattering process, however, a part of them, actually about 1% more or less, is emitted through the outlet without significant energy loss. Compared with the conventional micro-ion beam facilities, the present method is certainly simple and lowcost, thus providing an easy method of submicron Rutherford backscattering spectrometry or particle induced x-ray emission analyses. In addition, if the ion species are extended to heavier elements, the present method provides versatile maskless ion implantation techniques.