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Using atomic force microscopy (AFM/SFM), the strength of the adhesion between nanoparticles (NPs) and a flat gold surface was studied. By scanning in contact mode, a lateral force was applied to the NPs, depending on the cantilever stiffness and the setpoint value of the topography feedback. In this way, a threshold force for NP detachment was determined. The sample under investigation consisted of arrays of tungsten NPs deposited on top of a flat gold surface. The NPs were generated using electron beam deposition (EBD) and the precursor gas W(CO)6. Owing to the array‐wise arrangement of the NPs, any change in their position was comparatively easy to detect by deviation from the array points. The beam dwell time was employed as a parameter to control the NP size. The force threshold value for particle detachment was found to increase with the beam dwell time. Loose NPs moved by the scanning tip displayed increased lateral forces. These appeared in the lateral force images as continuous tracks. After expansion of the scan area such tracks were seen to mostly originate from the edges of the previous scans where the NPs had piled up. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Visible wavelength surface-enhanced Raman spectroscopy (SERS) has been observed from bovine serum albumin (BSA) using In-InP nanopillars synthesised by Ar gas cluster ion beam sputtering of InP wafers. InP provides a high local refractive index for plasmonic In structures, which increases the wavelength of the In surface plasmon resonance. The Raman scattering signal was determined to be up to 285 times higher for BSA deposited onto In-InP nanopillars when compared with Si wafer substrates. These substrates demonstrate the label-free detection of biomolecules by visible wavelength SERS, without the use of noble metal particles. Surface-enhanced Raman spectroscopy (SERS) utilises the resonant excitation of localised surface plasmons to boost the scattering efficiency from samples containing few or even single molecules 1-3. The technique's usefulness for non-destructive and label-free characterisation has resulted in a large body of research since its discovery in 1974 3,4. Gold and silver nanoparticles have historically been the most often employed SERS substrates due to their strong visible wavelength localised surface plasmon resonance (LSPR) 5,6. However, the price and scarcity of noble metals remains one of the major drawbacks of SERS and, as such, it has been recognised that more cost