In this letter, Si thin film (800 nm thick) with nanopillar array decorated surface is studied via simulation for its solar energy absorption characteristics. It is found that the light absorption is significantly enhanced due to the adding of the Si nanopillar (SiNP) array to the Si thin film. The absorption characteristics of the SiNP structure would be approximately optimum (especially at ∼2.5 eV, the high energy density region in the solar spectrum) when the periodicity of SiNP array is set as ∼500 nm, which can be explained when comparing the incident light wavelength with the periodicity of SiNP array.

In this letter, optimum periodic Si nanowire (SiNW) arrays are designed via simulation for solar cell application, in terms of the structural parameters, e.g., the array periodicity (P) and SiNW diameter (D). It is found that the more efficient light absorption compared to that of the Si thin film with the same thickness could be realized when P is between 250 and 1200 nm. Further, the ratio of D to P should be >0.5 (or more specifically ∼0.8) for the optimized solar energy harvesting. The underlying physics is also discussed in this work.

In recent years, with the general adoption of smartphones with computing power comparable to desktop computers, mobile applications (apps) have experienced a surge in popularity. However, there are a few studies conducted about their educational use, especially in Southeast Asia. To fill up this research gap, this study aims to provide a current overview of mobile apps usage in higher education. Besides exploring the actual use of apps, Technology Acceptance Model was applied to examine (1) undergraduate students' perceptions, which involve perceived usefulness (PU) and perceived ease of use (PEOU), towards adopting mobile apps for educational purposes, and (2) their overall attitude (OA) toward such adoption. Both quantitative and qualitative methods are used to collect data from 150 undergraduate students in Business, Education, and Engineering in Hong Kong. The results show undergraduate students use mobile apps frequently to engage in learning activities related to their academic studies, with a particularly focus on communication and collaborative working, accessing academic resources, and checking dictionary. However, the discrepancies in using apps for academic purposes are not significant between the three faculties. Meanwhile, PU has a more positive impact on OA compared with the impact of PEOU on OA. The investigation helps tertiary institutions, library service providers, and educators develop and assess the strategic planning for education collaborating with mobile apps. This paper could also give app developers some hints on the app design based on the actual usage and students' information needs.