Transmission probability and energy distribution of electrons impinging on indium thin film targets M. Hannachi, a Z. Rouabah, a N. Bouarissa b * and C. Champion c Based on a home-made Monte Carlo simulation, the electron backscattering coefficient, mean penetration depth, transmission probability, and transmission energy distribution of 1–5 keV electron normally incident penetrating in indium thin film targets have been computed. The trend of all features of interest as a function of the indium film thickness at both nanometric scale re- gion and bulk material region has been examined and discussed. The present predictions may be seen as the first investigation regarding 1–5 keV electrons impinging on indium thin film targets. Copyright © 2016 John Wiley & Sons, Ltd. Keywords: electron scattering; transmission; thin films; cross sections; indium Introduction Thin film materials play an important role in the development of several areas such as microelectronics, coatings, and transmission electron microscopy. [1] As a matter of fact, their properties are quite different from those of the bulk materials from which they are made of. They have a wide range of applications in microelectronic devices and biological science. They have also been used for pro- tection of materials from corrosion, oxidation, and wear. The devel- opment of material science and semiconductor technology makes it possible to deal with films’ thicknesses of several nanometers, leading to new applications in the areas of solar energy conversion, nanostructures, and nanomaterial coatings. The investigation of electron transmission and backscattering from thin film materials is an important tool for the determination of the film thickness ranging from angstrom to submicron [2,3] and has an impact on techniques of surface science. [4] So far, several studies have been reported on electron impinging on semi-infinite solid targets [5–10] ; however, only a little has been known about electron penetration in thin film targets, [11,12] espe- cially in the low-energy regime. Electron-beam matter interaction has been treated by using various theoretical approaches. However, with the rapid evolution of computer calculation capability, the Monte Carlo method becomes the most powerful and reliable procedure for the investigation of low-energy (keV) electrons im- pinging on solid targets. [5,7,13–15] The electron–matter interaction modeled by using Monte Carlo approach aims to simulate the elas- tic and the inelastic scattering processes as accurately as possible. Hence, the accuracy of the Monte Carlo method depends on the description of the scattering processes employed in the simulation. The present study is undertaken in order to focus on 1–5 keV electrons impinging on indium (In) thin film targets with normal an- gle of incidence. To the best of our knowledge, this is the first time that such a study has been made for such a material of interest. A home-made Monte Carlo simulation approach has been used to predict accurate electron backscattering coefficients, mean pene- tration depths, transmission probabilities, and transmission energy distributions and to examine their dependence on In film thickness. The target material of interest has been chosen based on its impor- tance for several technological applications which include its use as a thermal interface material, as light-emitting diodes, and in thin film solar cells. Theoretical treatment and computation Monte Carlo methods require an accurate description of the pro- cesses by which electrons are slowed down in the solid target. For this, the elastic scattering process is in the present contribution described by using a modified Rutherford differential cross sections as described in details in our recent published paper. [16] The inelastic processes are modeled by using the Gryzinski’s ex- citation function expressions [17–19] for both core and valence elec- tron excitations. The total inelastic scattering cross section has been calculated following the same procedure as that reported by Bouarissa and described in more details in Ref. [20] . The present simulation has been carried out by adopting a spherical polar coordinate system (r, θ, and ɸ) in such a way that the z-axis is normal to the sample surface. ɸ here is the azimuthal scattering angle. The latter is assumed to be distributed in a uni- form manner in the range of [0 À 2π]. The results presented in * Correspondence to: N. Bouarissa, Laboratory of Materials Physics and its Applications, University of M’sila, 28000 M’sila, Algeria. E-mail: n_bouarissa@yahoo.fr a Laboratoire Matériaux et Systèmes Electroniques (LMSE), Université de Bordj-Bou- Arreridj, El-Anasser, 34265, Bordj-Bou-Arreridj, Algeria b Laboratory of Materials Physics and its Applications, University of M’sila, 28000, M’sila, Algeria c CNRS/IN2P3, Centre d’Etudes Nucléaires de Bordeaux-Gradignan (CENBG), Université de Bordeaux 1, Bordeaux, France Surf. Interface Anal. 2016 Copyright © 2016 John Wiley & Sons, Ltd. Research article Received: 14 October 2016 Accepted: 7 November 2016 Published online in Wiley Online Library (wileyonlinelibrary.com) DOI 10.1002/sia.6194