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This study examined the effect of the hydrogen ratio on the electrical and optical properties of hydrogenated Al-doped zinc oxide (AZO) thin films deposited by rf magnetron sputtering using a ceramic target (98 wt% ZnO, 2 wt% Al 2 O 3 ). Various AZO films on glass were prepared by changing the H 2 /(Ar+H 2 ) ratio at room temperature. The AZO/H films showed a lower resistivity and a higher carrier concentration and mobility than the AZO films. However, the resistivity and mobility of the AZO/H films increased and decreased with increasing H 2 flow ratio, respectively. As a result, the AZO/H films grown with 2% H 2 addition showed excellent electrical properties with a resistivity of 4.98 × 10 4 Ωcm. The UV-measurements showed that the optical transmission of the AZO/H films was >85% in the visible range with a wide optical band gap. In addition, the effect of H 2 flow ratio on the structure and composition of hydrogenated AZO thin films have also been studied.

The performance enhancement of polycrystalline Si solar cells by using an optimized discrete multilayer anti-reflection (AR) coating with broadband and omni-directional characteristics is presented. Discrete multilayer AR coatings are optimized by a genetic algorithm, and experimentally demonstrated by refractive-index tunable SiO₂ nano-helix arrays and co-sputtered (SiO₂)x(TiO₂)₁₋x thin film layers. The optimized multilayer AR coating shows a reduced total reflection, leading to the high incident-photon-to-electron conversion efficiency over a correspondingly wide range of wavelengths and incident angles, offering a very promising way to harvest more solar energy by virtually any type of solar cells for a longer time of a day.

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