The advantages conferred by these traits have seen Si nanostructures being Selleckchem PR171 applied in nanoelectronics for transistor miniaturization [1–3], photovoltaics for exceptional light trapping [4–6], and photodetection for ultrahigh photoresponsivity [7]. Si nanostructures such as Si nanowires (SiNWs) have also enabled ultra-sensitivity to be realized in chemical and biological sensing [8], efficient thermoelectric performance [9], enhanced performance in Li-ion batteries [10], and nanocapacitor arrays [11]. Successful realization of Si-nanostructured devices on a manufacturing scale, however,

requires practical techniques of producing the nanostructures with controlled dimensions, patterns, crystalline structures, and electronic qualities. Metal-assisted chemical etching (MACE) or metal-catalyzed electroless etching (MCEE) is a simple technique first demonstrated by Peng et al., which can be used to generate high aspect ratio Si nanostructures [12, 13]. In this manuscript, this technique is referred to as MCEE because this provides a more explicit description of the process. Sidewall inclination common in reactive ion etching (RIE) [14] and scalloping SB431542 datasheet effects typical of deep reactive ion etching [15] are avoided in MCEE. The process does not require the complex precursors used in vapor-liquid-solid growth or chemical vapor deposition, and the expensive equipment

of inductive coupled plasma-RIE or DRIE. Properties such as doping level and type, crystal orientation, and quality are determined simply by the starting Si wafers. Approaches combining nanoscale FHPI clinical trial patterning techniques with MCEE have been reported. The combination allows more control over the order, diameter, and density dipyridamole of the Si nanostructures. This was demonstrated with

nanosphere lithography which is based on the self-assembly of a monolayer of nanospheres (e.g., polystyrene [16] or silica [17]) into ordered hexagonal close-packed arrays. However, ordering of the nanospheres and the resulting Si nanostructures are limited to domains. Huang et al. employed an anodic aluminum oxide (AAO) template and a Cr/Au evaporation step to define the mask for catalytic etching to form SiNWs [18]. While this is a simple and cost-effective method, the positions of the nanostructures are limited to short-ranged hexagonal arrangements, and large-scale production will likely be hampered by inefficient AAO template transfer to the Si substrate. Lately, block copolymer lithography has been paired with MCEE to produce highly dense Si nanostructure arrays. But a distribution of dimensions exists, and ordered arrangement is limited to small areas [19]. In order to fabricate Si nanostructures with various array configurations, cross-sectional shapes, and perfect ordering over large areas, interference lithography (IL) in combination with MCEE has been employed by Choi et al. [20].