Gypsum: an environment-friendly, inexpensive and robust height calibration standard at nanometer-scale for atomic force microscopy.

Gypsum is an Earth-abundant mineral with enormous applications in agriculture and civil engineering. Here, we show it is also an excellent height calibration standard alternative for atomic force microscopy (AFM). Using plain water as etchant, gypsum flakes readily review 0.75 nm tall terraces which are easy to image (lateral dimensions from tens to hundreds of nanometers) and robust against time in ambient conditions. Therefore, the present work demonstrates a new height standard alternative which is easily-available for all AFM microscopists around the world.

Controlled growth and positioning of metal nanoparticles via scanning probe microscopy.

A process enabling both the controlled growth and positioning of metal nanoparticles (NPs) is reported. Using scanning probe microscopy (SPM) techniques, metal NPs are directly grown in the region of interest via the reduction of metallic ions in a polymer matrix induced by a properly biased SPM tip. The metallic nature of these NPs is established via X-ray diffraction and surface-enhanced Raman spectroscopy experiments. Some initial applications of this process, such as the decoration of carbon nanotubes with metal NPs, are also briefly demonstrated and discussed.