title: Influence of the narrow {111} planes on axial and planar ion channeling.
abstract: We report channeling patterns where clearly resolved effects of the narrow {111} planes are observed in axial and planar alignments for 2 MeV protons passing through a 55 nm [001] silicon membrane. At certain axes, such as <213> and <314>, the offset in atomic rows forming the narrow {111} planes results in shielding from the large potential at the wide {111} planes, producing a region of shallow, asymmetric potential from which axial channeling patterns have no plane of symmetry. At small tilts from such axes, different behavior is observed from the wide and narrow {111} planes. At planar alignment, distinctive channeling effects due to the narrow planes are observed. As a consequence of the shallow potential well at the narrow planes, incident protons suffer dechanneled trajectories which are excluded from channeling within the wide planes, resulting in an anomalously large scattered beam at {111} alignment.
authors.affiliation: Center for Ion Beam Applications, Physics Department, National University of Singapore, Lower Kent Ridge Road, Singapore 117542.
authors.forename: M
authors.initials: M
authors.lastname: Motapothula
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Dang
authors.forename: T
authors.initials: T
authors.lastname: Venkatesan
authors.forename: M B H
authors.initials: MB
authors.lastname: Breese
authors.forename: M A
authors.initials: MA
authors.lastname: Rana
authors.forename: A
authors.initials: A
authors.lastname: Osman