An analytical energy-loss line shape for high depth resolution in ion-beam analysis

Abstract

The knowledge of the energy-loss distribution in a single ion-atom collision is a prerequisite for subnanometric resolution in depth-profiling techniques such as Nuclear Reaction Analysis (NRA) and Medium Energy Ion-Scattering (MEIS). The usual Gaussian approximation specified by the stopping power and energy straggling is not valid for near surface regions of solids, where subnanometric or monolayer resolution can be achieved. In this work we propose an analytical formula for the line shape to replace the usual Gaussian distribution widely used in low-resolution ion-beam analysis. Furthermore, we provide a simple physical method to derive the corresponding shape parameters. We also present a comparison with full coupled-channel calculations as well as with experimental data at nearly single collision conditions.

Role of electronic excitations in the energy loss ofH2+projectiles in high-κmaterials

“…The effect of the energy loss in the backscattering collision is calculated according to Ref. 29. In this code, all experimental factors and physical properties of the target such as structure ͑bulk or layered͒, thickness, density and atomic composition serve as input parameters.…”

Spin and energy relaxation in germanium studied by spin-polarized direct-gap photoluminescence

“…We thus modeled the lineshape of the PL spectra by using the following exponentially modified Gaussian distribution, i.e. the convolution of an exponentially decaying function and a normal distribution 40 :…”

Skimming-trajectory effect for energy loss of medium-energy He ions passing along major crystal axes of KI(001) and RbI(001)

“…For this purpose, it is essential to see the hitting probability for the atoms of each layer as well as the line shape for each scattering component. Concerning the latter, we employed the exponentially modified Gaussian (EMG) line shape [12,13] and the Lindhard-Scharff formula [14] to calculate the energy straggling, whose reliabilities were confirmed experimentally in advance [13,[15][16][17]. The hitting probability for the atoms of each layer is calculated by Monte Carlo (MC) simulations of ion trajectories, which are explained in detail below.…”

“…The surface peaks are decomposed into three scattering components from the top-, second-, and third-layer I and Rb atoms (solid curves). Note that the shadowing effect was weakened owing to large root-mean-square thermal vibration amplitudes expected from the low Debye temperature of 115 K. Here, we employed the EMG function as the line shape [12,13]. The best fit was obtained by assuming the energy differences ( E 1−2 ) of 520 ± 20 and 540 ± 30 eV between the scattering components from the top-and second-layer I and Rb atoms, respectively.…”