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   As alternative route to fabricate silicon nanostructures, wet etching processes such as electrochemical and electroless etching of silicon have attracted intensive interests recently, due to their simple cost-effective solution based process.    Electrochemical etching of silicon in hydrofluoric acid solutions generally results in either porous silicon formation or electro-polishing at low or at high current densities, respectively. In an intermediate regime, pores merged resulting in free standing silicon wires. Regular pore and wire array could be obtained if etc…

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 In the past, despite the record efficiencies achieved, complicated and expensive processes has made the commercial manufacture of high efficiency cells uneconomical. The double layer antireflection coatings by thermal evaporation have needed to be removed, modified or replaced for successful commercialization. The subwavelength Si nanowire (SiNW) arrays which is fabricated cost-efficient metal-assisted electroless etching (MAE) eliminate the need for conventional vacuum-deposited antireflection coatings. The optical features of SiNW arrays stem mainly from reflectance suppression vi…

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     Crystalline Si photovoltaics benefits from more than half a century of experience in Si microelectronics. The photovoltaic material Si is abundant in the earth’s crust and is environmentally benign. The main obstacle for a wider spread of crystalline silicon photovoltaics is the high cost of crystalline Si wafers that have a typical thickness of 300μm and account for about 50% of the module costs. The reduction of the Si consumption is the driving force for the world-wide increasing interest in the development of thin film modules.  To make the flexible thin film…

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Optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has been considered as an ideal candidate for more efficiently harnessing solar energy. This focuses mostly on partitioning of the solar spectrum into ultraviolet/visible region for PV and infrared region for TE. Especially for PV-TE stack approaches, the TE part aims mainly for converting the transmission and thermali-zation losses from a sun-sided PV device to useful electrical energy.  Enhancing the utilization of solar energy and waste heat recovery are broad societal demand to resolve global energy crisis bec…

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A photoelectrochemical cell (PEC) harnesses sunlight to produce hydrogen gas (H2) via water splitting. Silicon (Si) is abundant and widely used as a photovoltaic semiconductor material. Si has also been utilized as a photocathode in PEC owing to outstanding physical properties, including an optimal bandgap (Eg ≈ 1.1 eV) allowing for the absorption of a large portion of solar spectral irradiance, and the position of the conduction-band edge, which is higher than the proton reduction potential.  Recent attempts to improve the H2 evolution efficiency in PEC systems through the applicatio…