1. Photoluminescence and surface photovoltage of ethynyl derivative‐terminated Si(111) surfaces
- Author
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Florent Yang, Ralf Hunger, Jörg Rappich, and Klaus Rademann
- Subjects
Photoluminescence ,Passivation ,business.industry ,Band gap ,Chemistry ,Surface photovoltage ,Nanotechnology ,Carrier lifetime ,Condensed Matter Physics ,Covalent bond ,Microelectronics ,Physical chemistry ,Surface charge ,business - Abstract
Functionalisation of Si surfaces by organic molecules is of high interest for a wide range of possible applications such as Si based sensors [1-3], photovoltaics [4], microelectronics [5, 6] or bio-chips [7]. Hydrogenated Si(111) surfaces have a low rate of surface charge carrier recombination, which means that this sur-face is well-passivated [8]. However, this surface is not stable and oxidizes rapidly in contact with ambient air [9]. For this reason, a way to avoid this degradation is to form covalent Si-C bonds which can be obtained by various methods initiated chemically [10], electrochemically [11, 12], thermally [13] or photochemically [14]. Such modi-fied surfaces are expected to exhibit a better chemical sta-bility and good electronic passivation (low concentration of interface states in the band gap) [15, 16]. Pulsed PL and SPV are two complementary methods to obtain informa-tions about the amount of non-radiative active defect cen-ters at the interface and to measure the minority carrier lifetime and diffusion length [17, 18]. In this work, electrochemical processing has been cho-sen as method to graft ethynyl derivatives onto Si(111) sur-faces by the use of Grignard reagents. Recently, it has been shown that this electrochemical grafting method lead to formation of polymeric layers with thicknesses of about 10-20 nm when a charge flow of 450 mC/cm
- Published
- 2010
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