Effect of substrate thickness on ejection of phenylalanine molecules adsorbed on free-standing graphene bombarded by 10 keV C60

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:393

Article; Proceedings Paper

Golunski, M.¹  Verkhoturov, S. V.²  Verkhoturov, D. S.²  Schweikert, E. A.²  Postawa, Z.¹ 

[1] Jagiellonian Univ, Inst Phys, Ul Lojasiewicza 11, PL-30348 Krakow, Poland

[2] Texas A&M Univ, Dept Chem, College Stn, TX 77840 USA

关键词: Computer simulations;    Sputtering;    Cluster projectiles;    Graphene;    Organic overlayers;   

DOI  :  10.1016/j.nimb.2016.09.006

来源: Elsevier

【 摘 要 】

Molecular dynamics computer simulations have been employed to investigate the effect of substrate thickness on the ejection mechanism of phenylalanine molecules deposited on free-standing graphene. The system is bombarded from the graphene side by 10 keV C-60 projectiles at normal incidence and the ejected particles are collected both in transmission and reflection directions. It has been found that the ejection mechanism depends on the substrate thickness. At thin substrates mostly organic fragments are ejected by direct collisions between projectile atoms and adsorbed molecules. At thicker substrates interaction between deforming topmost graphene sheet and adsorbed molecules becomes more important. As this process is gentle and directionally correlated, it leads predominantly to ejection of intact molecules. The implications of the results to a novel analytical approach in Secondary Ion Mass Spectrometry based on ultrathin free-standing graphene substrates and a transmission geometry are discussed. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free