A photoluminescence (PL) response (S-band) of porous silicon to specific amounts of organic vapors of n-hexane, toluene and methanol in gas phase reveals the presence of two reversible processes: one relatively fast responsible for PL quenching and one relatively slow which is responsible for a remarkable PL enhancement. The fast PL quenching (with time constant of several seconds) can be utilized for sensing the studied organic vapors within a concentration range of about 1±500 ppm.Introduction Porous silicon (PS) attracts much interest during the last decade due to its efficient photoluminescence (PL) in the visible region. Considerable effort has been devoted to optimization of PL efficiency and PL wavelength tunability. Most of the studies were performed bearing in mind potential applications for electroluminescence (EL) devices. The main drawback of EL from PS is its instability due to its reactive surface [1]. This drawback of PS large reactive surface can be, on the other hand, utilized for sensing applications. Various sensor properties of PS have been studied in gas phase, e.g. conductivity [2], refractive index [3], PL quenching [4,5,6]. Despite an enormous amount of performed studies understanding of the PL mechanism and surface chemistry of PS still remains a great challenge.We report on time evolution of PL response from PS in presence of various vapors of organic compounds. We evidence, for the first time, that two processes are responsible for the PL response: a fast PL quenching and a relatively slow PL enhancement. At present, we cannot specify the mechanism of the PL enhancement process. We demonstrate the application of the fast PL quenching process for gas sensing purposes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.