Monoclinic gallium oxide thin films were grown on (0001) sapphire at various substrate temperatures ranging from 400 to 1000 °C by pulsed laser deposition using a KrF excimer laser. The structural, optical and compositional properties of the films were analyzed by using x-ray diffraction, transmission electron microscopy, optical transmittance, and Rutherford backscattering spectroscopy. As the substrate temperature was increased to 800 °C, the gallium oxide film possesses single crystalline phase with a preferred growth orientation of (−201) plane and higher crystal quality than those at the other temperatures. Optical transmittance measurements reveal the films grown at 600-1000 °C exhibit a clear absorption edge at the deep ultraviolet region around 250 nm wavelength. Based on the results of Rutherford backscattering spectroscopy, the O/Ga ratio of gallium oxide film increased gradually with increasing substrate temperature. When the substrate temperature was raised to 800-1000 °C, the film composition was close to the formation of Ga 2 O 3 , indicating the O vacancies and defects were reduced. Furthermore, the films grown at 600 and 800 °C were chosen to fabricate solar-blind metal-semiconductor-metal photodetectors. At an applied bias of 5 V, the photodetector prepared with 800 °C-grown film has a lower dark current of 1.2 × 10 −11 A and a higher responsivity of 0.903 A/W (at a wavelength of 250 nm) than those with 600 °C-grown films. The better device performance is ascribed to the higher crystal quality and fewer O vacancies in the 800 °C-grown film. Moreover, the results indicate the gallium oxide films presented in this study have high potential for deep ultraviolet photodetector applications.

The number of people with dementia is increasing rapidly worldwide. Developing strategies to improve quality of life for those with dementia is crucial and is receiving more attention. Natural environments are known for their healing effects on most people. This pilot study aimed to understand the benefits that natural environments, such as gardens, can provide for people with dementia. In total, 42 staff members in nine dementia care facilities were recruited as participants in this study and answered a semistructured questionnaire. One-way analysis of variance with repeated measures and the Mann-Whitney U test were used to compare the effects of garden visits on evaluated characteristics and the differences in evaluated characteristics between free garden use and unfree garden use groups. Data from open-ended questions underwent text analysis to obtain the principal beliefs of the participants. The staff members reported that garden visits had positive effects on mood, social interaction, depression, and agitation in people with dementia because of the multisensory, gentle stimuli of the natural environment. Of the evaluated cognitive characteristics, attention and orientation to time were improved the most after residents with dementia had spent time in a garden. Additionally, staff members in the free garden use group scored the effects of garden visits on the mood, long-term memory, language abilities, spatial ability, aggression, and agitation of patients with dementia as significantly higher than staff members in the unfree garden use group. Recommendations for future studies are discussed.

In this work, hafnium oxide (HfO 2 ) thin films are deposited on p-type Si substrates by remote plasma atomic layer deposition on p-type Si at 250 °C, followed by a rapid thermal annealing in nitrogen. Effect of post-annealing temperature on the crystallization of HfO 2 films and HfO 2 /Si interfaces is investigated. The crystallization of the HfO 2 films and HfO 2 /Si interface is studied by field emission transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and atomic force microscopy. The experimental results show that during annealing, the oxygen diffuse from HfO 2 to Si interface. For annealing temperature below 400 °C, the HfO 2 film and interfacial layer are amorphous, and the latter consists of HfO 2 and silicon dioxide (SiO 2 ). At annealing temperature of 450-550 °C, the HfO 2 film become multiphase polycrystalline, and a crystalline SiO 2 is found at the interface. Finally, at annealing temperature beyond 550 °C, the HfO 2 film is dominated by single-phase polycrystalline, and the interfacial layer is completely transformed to crystalline SiO 2 .

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In this study, ZnS thin films were prepared on glass substrates by chemical bath deposition at various Zn/S molar ratios from 1/50 to 1/150. The effects of Zn/S molar ratio in precursor on the characteristics of ZnS films were demonstrated by X-ray diffraction, scanning electron microscopy, optical transmittance, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrometry. It was found that more voids were formed in the ZnS film prepared using the precursor with Zn/S molar ratio of 1/50, and the other ZnS films showed the denser structure as the molar ratio was decreased from 1/75 to 1/150. From the analyses of chemical bonding states, the ZnS phase was indeed formed in these films. Moreover, the ZnO and Zn(OH)2also appeared due to the water absorption on film surface during deposition. This would be helpful to the junction in cell device. With changing the Zn/S molar ratio from 1/75 to 1/150, the ZnS films demonstrate high transmittance of 75–88% in the visible region, indicating the films are potentially useful in photovoltaic applications.