▎ 摘　　要

We study the transmission of electron beams with a finite angular extent through symmetric and asymmetric multi-barrier structures in graphene with the aim of enhancing the functionality of nanodevices. The barriers in graphene are created by applying electrostatic voltages on narrow gate electrodes. We found that, besides modulating the transmission coefficient of obliquely incident electrons, such structures can narrow electron beams, split them into two parts with tunable intensities, and even steer them by slightly modifying the gate voltage. (C) 2012 Elsevier B.V. All rights reserved.