Abstract

Silicon (Si) is the essential elemental semiconductor of modern microelectronic devices (Canham 2014). Since silicon itself does not conduct electricity as efficiently as conventional metallic conductors (e.g., copper), the doping of different elements in silicon, particularly arsenic and boron, to transform it into n-type and p-type, respectively, is a strategy to perturb the lattice structure. This enhances the conductivity of the material and permits operation most commonly as a transistor (Brus 1994; Canham 2014). Although three-dimensional bulk crystalline silicon has played a dominant role in the development of electronic technologies in the past few decades, an interest in nanoscale Si has received widespread investigation (Murphy and Coffer 2002; Elbersen 2015). When the Si feature size is in the 1–100 nm range, quantum confinement effects can emerge and significantly alter the properties and performance of the material (Pavesi and Lockwood 2004). Notably, in the 1990s, the discovery of efficient room temperature, visible light emission from nanostructured, two-dimensionally confined porous silicon (pSi) has intrigued scientists around the world. Since then, extensive research has been conducted to investigate new properties and applications of this material (Cullis and Canham 1991). Furthermore, studies of pSi have been extended to biorelevant applications including drug delivery, tissue engineering, and biosensing—a consequence of its biocompatibility and biodegradability (Coffer et al. 2005; Anglin et al. 2008; Salonen et al. 2008, Santos et al. 2014). The properties of pSi are well governed by its surface chemistry and porous morphology, thereby rendering an ability to modulate this material for a number of specific purposes (Canham 2014).