Hard X-ray beam damage study of monolayer Ni islands using SX-STM
- PDF / 649,750 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 114 Downloads / 151 Views
Hard X-ray beam damage study of monolayer Ni islands using SX-STM Nozomi Shirato1,*, Marvin Cummings1, Heath Kersell2, Yang Li2, Dean Miller3, Daniel Rosenmann3, Saw-Wai Hla2, 3, Volker Rose1, 3,** 1
Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA. Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, OH 45701, USA. 3 Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, USA. 2
Corresponding authors: *(N.S.) [email protected]; **(V.R.) [email protected] ABSTRACT X-ray beam-induced damage in nanoscale metal islands was investigated. Monolayer-high Ni islands were prepared on a Cu(111) substrate. High brilliance X-rays with photon energies between 8.45 and 8.85 keV illuminated the sample for about 11 hours. In order to track changes in the morphology of the islands, the synchrotron X-ray scanning tunneling microscopy (SX-STM) technique was utilized. The result shows that X-ray illumination onto Ni islands does not induce noticeable damage. The study demonstrates that local beam-induced changes can be studied using SX-STM. INTRODUCTION High brilliance X-ray beams produced by third generation synchrotrons are a powerful source for sample analysis. The high flux density enhances signal-to-noise ratios and reduces data acquisition times. However, typically a sample irradiated by a high radiation dose tends to exhibit beam-induced damage, e.g., modifications of the chemical compositions of organic molecules or changes in the surface structure due to thermal annealing. It is necessary to monitor and quantify beam-induced damages for efficient data acquisition and sample preservation purposes. Various types of studies have been carried out to quantify beam-induced damage. Measuring changes in diffraction peaks intensity [1–3] and X-ray absorption near edge structure (XANES) spectroscopy [4, 5] are commonly used methods to observe X-ray beam damage. However, these techniques provide information about changes of the chemical composition and structure averaged over the entire area that is illuminated by the beam. They do not provide any direct localized information about changes in the surface chemistry or topography. Nevertheless, it is essential to characterize localized beam damage during X-ray illumination, in order to obtain a better understanding of complex systems, such as biological cells, batteries and nanostructures [6]. This goal can be achieved when a scanning tunneling microscope (STM) is used to image a sample surface during X-ray illumination [7]. Over the last decade, groups around the world have been developing instruments combining synchrotron X-ray illumination and STM [8–11]. Recently, synchrotron X-ray scanning tunneling microscopy (SX-STM) showed the capability to measure twodimensional real space information of monolayer thick metal islands during X-ray
illumination [12]. Here we present a study of potential hard X-ray beam-induced damage of monolayer Ni islands on a Cu(111) substrate using SX-STM. The techn
Data Loading...
