Journal of Electron Spectroscopy and Related Phenomena 151 (2006) 71–77 Backscattering of 8–28 keV electrons from a thick Al, Ti, Ag and Pt targets R.K. Yadav, R. Shanker ∗ Atomic Physics Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India Received 2 October 2005; received in revised form 1 November 2005; accepted 2 November 2005 Available online 6 December 2005 Abstract Measurements of electron backscattering coefficient η for thick Al, Ti, Ag and Pt targets have been made for incident electrons with energy 8–28keV. The variations of η with angle of incidence α, impact energy E 0 and with target atomic number Z have been studied. The data are compared with available theories. The mean fractional energy absorbed in the backscattering process has been determined and compared with an analytical expression and with Monte-Carlo simulations based on the Kanaya and Okayama electron–electron and electron–nucleus interactions and on the Quinn electron–plasma interactions. The comparison between our experimental data and the model calculations using Monte-Carlo simulations and analytical expression shows a reasonably good agreement among themselves within experimental errors of measurements. © 2005 Elsevier B.V. All rights reserved. PACS: 79.90.+b; 79.20.H x Keywords: Backscattering coefficient; Mean fractional energy absorbed; Diffusion range; Penetration depth 1. Introduction The technique of surface analysis has become extremely important in modern technology [1,3]. The interaction of elec- tron beam with a solid target has been studied since long [4–9]. Excellent reviews about this subject are given by Bothe [10], Birkhoff [11] and more recently by Neidrig [12], Goldstein et al. [13], Newbury et al. [14] and Feldman and Mayer [15]. When a mono-energetic electron beam impinges on a solid target, some electrons are backscattered without any energy loss. This elastic electron backscattering process plays an important role in many experimental techniques, like, low energy electron diffraction (LEED), scanning electron microscopy (SEM), electron probe microanalysis (EPM), Auger electron spectroscopy (AES), elec- tron lithography physics, radiation damage and elastic peak technique. These techniques have been used for the experimen- tal determination of the inelastic mean free paths (IMFPs) of electrons in the solid. It has become essential to have a precise knowledge of the surface structure and the surface chemical ∗ Corresponding author. Tel.: +91 542 316801x7309; fax: +91 542 317074. E-mail address: rshanker@bhu.ac.in (R. Shanker). composition as well as to understand the surface properties of a solid material. Indeed, any interaction between a solid and the “outside world” takes place through the topmost atoms of the surface of the material. It has then become extremely common to treat, coat, etc., the surface of the material to modify the way in which it interacts with the environment (passivation of the surface against corrosion, coating of glasses to avoid unwanted reflection, etc.). It is then extremely important to control at a microscopic level the way in which the surface treatments affect the interactions of the solid with the “outside worlds” to under- stand the chemical reactions at the surface of a material, to understand how the electronic surface properties (which differ from those of bulk) affect the behavior of an electronic device, etc. It is well known that when an electron beam impinges on the solid targets, a fraction of the beam is absorbed, another fraction is backscattered, and remaining one is transmitted. The sum of these fractions is equal to 1. Their values depend on the nature of a target bombarded and its thickness. If the target thickness is greater than the maximum penetration range R, then no electrons are transmitted through the specimen, the incident electrons can be only absorbed or backscattered and the fraction of backscat- tered electrons assumes its maximum value generally indicated as backscattering coefficient η. For understanding the surface 0368-2048/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.elspec.2005.11.002