Although the benefits of decreased sample temperature for the molecular profiling of organic materials with time-of-flight secondary ion mass spectrometry (TOF-SIMS) have been established, the mechanism behind spectral changes observed at low temperature, particularly increased protonated molecular ion (M + H)(+) yields, have not been examined in detail. We have developed a procedure to investi...

High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium dis...

We present a molecular dynamics (MD) based computer simulation model for particle bombardment of metal surfaces. In addition to the description of the atomic collision cascade initiated by the particle impact, our model incorporates the electronic degree of freedom of the target and therefore is capable of simultaneously predicting secondary ion formation in sputtering as well as ion-bombardmen...

Variable-temperature scanning tunneling microscopy is used to characterize surface defects created by 4.5 keV He ion bombardment of Si(001) at 80–294 K; surface defects are created directly by ion bombardment and by diffusion of bulk defects to the surface. The heights and areal densities of adatoms, dimers, and adatom clusters at 80 and 130 K are approximately independent of temperature and in...

Ion bombardment of crystalline silicon targets induces pattern formation by the creation of mobile surface species that participate in forming nanometer-scale structures. The formation of these mobile species on a Si 001 surface, caused by sub-keV argon ion bombardment, is investigated through molecular dynamics simulation of Stillinger-Weber Phys. Rev. B 31, 5262 1985 silicon. Specific criteri...

Recent experimental studies focusing on the morphological properties of surfaces eroded by ion-bombardment report the observation of self-affine fractal surfaces, while others provide evidence about the development of a periodic ripple structure. To explain these discrepancies we derive a stochastic growth equation that describes the evolution of surfaces eroded by ion bombardment. The coeffici...

A buckminsterfullerene ion source is employed to characterize peptide-doped trehalose thin films. The experiments are designed to utilize the unique sputtering properties of cluster ion beams for molecular depth profiling. The results show that trehalose films with high uniformity can be prepared on Si by a spin-coating technique. Bombardment of the film with C60+ results in high quality time-o...

We present differential sputter yield measurements of boron nitride due to bombardment by xenon ions. A four-grid ion optics system is used to achieve a collimated ion beam at low energy (<100 eV). A quartz crystal microbalance (QCM) is used to measure differential sputter yield profiles of condensable components from which total sputter yields can also be determined. We report total and differ...

A protocol for three-dimensional molecular thin-film analysis is described that utilizes imaging time-of-flight secondary ion mass spectrometry and large-area atomic force microscopy. As a test study, a 300-nm trehalose film deposited on a Si substrate was structured by bombardment with a focused 15-keV Ga+ ion beam and analyzed using a 40-keV C60+ cluster ion beam. A three-dimensional sputter ...