Zinc oxide (ZnO) films have been grown on gold (111) by electrodeposition using two different OH− sources, nitrate and peroxide, in order to obtain a comparative study between them. The morphology, structural and optical characterization of the films were investigated depending on the solution used (nitrate and peroxide) and the applied potential. Scanning electron microscopy pictures show different morphologies in each case. X-ray diffraction confirms that the films are pure ZnO oriented along the (0002) direction. ZnO films have been studied by photoluminescence to identify the emission of defects in the visible range. A consistent model that explains the emissions for the different electrodeposited ZnO films is proposed. We have associated the green and yellow emissions to a transition from the donor OH− to the acceptor zinc vacancies (VZn−) and to interstitial oxygen (Oi0), respectively. The orange-red emission is probably due to transitions from the conducting band to Oi− and OZn0 defects and the infrared emission to transition from these Oi−/2− and OZn0/− defects to the valence band.

This paper presents an overview of experimental results and progress made in investigating density control using Li-coating, transport and L–H transitions in TJ-II. The Li-coating changes drastically the plasma–wall interaction, decreasing the recycling, and enlarges substantially the operational range of the device delaying the appearance of radiative collapse that happens for higher densities, which permits confinement properties of much denser plasmas to be studied. Moreover, L–H mode transition has only been achieved after Li-coating in TJ-II. The effect of rational surfaces on heat transport is studied showing a decrease in heat diffusivity close to their position, and it is also seen that rational surfaces located in the edge make L–H transition easier. TJ-II findings provide a new guideline for understanding the trigger mechanism of the L–H transition pointing out the importance of low frequency fluctuating sheared E × B flows. The properties of fast-ion confinement are described as well as the effects of impurities on radiation profiles, showing two types of profiles the bell and the dome shape, the latter being more prone to radiative collapse.

TJ-II stellarator results on modelling and validation of plasma flow asymmetries due to on-surface potential variations, plasma fuelling physics, Alfvén eigenmodes (AEs) control and stability, the interplay between turbulence and neoclassical (NC) mechanisms and liquid metals are reported. Regarding the validation of the neoclassically predicted potential asymmetries, its impact on the radial electric field along the flux surface has been successfully validated against Doppler reflectometry measurements. Research on the physics and modelling of plasma core fuelling with pellets and tracer encapsulated solid pellet injection has shown that, although post-injection particle radial redistributions can be understood qualitatively from NC mechanisms, turbulence and fluctuations are strongly affected during the ablation process. Advanced analysis tools based on transfer entropy have shown that radial electric fields do not only affect the radial turbulence correlation length but are also capable of reducing the propagation of turbulence from the edge into the scrape-off layer. Direct experimental observation of long range correlated structures show that zonal flow structures are ubiquitous in the whole plasma cross-section in the TJ-II stellarator. Alfvénic activity control strategies using ECRH and ECCD as well as the relation between zonal structures and AEs are reported. Finally, the behaviour of liquid metals exposed to hot and cold plasmas in a capillary porous system container was investigated.