Design of Atomically Precise Nanoscale Negative Differential Resistance Devices. Issue 2 (20th December 2018)

• Record Type: Journal Article
• Authors: Xiao, Zhongcan; Ma, Chuanxu; Huang, Jingsong; Liang, Liangbo; Lu, Wenchang; Hong, Kunlun; Sumpter, Bobby G.; Li, An‐Ping; Bernholc, Jerzy
• Is Part Of: Advanced theory and simulations. Volume 2:Issue 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-20
• Subjects: atomically precise devices -- band alignment engineering -- graphene nanoribbons -- negative differential resistance; Science -- Simulation methods -- Periodicals; Science -- Methodology -- Periodicals; Engineering -- Simulation methods -- Periodicals; Engineering -- Methodology -- Periodicals; 507.21
• DOI: 10.1002/adts.201800172
• Languages: English
• ISSNs: 2513-0390

Abstract

Abstract: Downscaling device dimensions to the nanometer range raises significant challenges to traditional device design, due to potential current leakage across nanoscale dimensions and the need to maintain reproducibility while dealing with atomic‐scale components. Here, negative differential resistance (NDR) devices based on atomically precise graphene nanoribbons are investigated. The computational evaluation of the traditional double‐barrier resonant‐tunneling diode NDR structure uncovers important issues at the atomic scale, concerning the need to minimize the tunneling current between the leads while achieving high peak current. A new device structure consisting of multiple short segments that enables high current by the alignment of electronic levels across the segments while enlarging the tunneling distance between the leads is proposed. The proposed structure can be built with atomic precision using a scanning tunneling microscope (STM) tip during an intermediate stage in the synthesis of an armchair nanoribbon. An experimental evaluation of the band alignment at the interfaces and an STM image of the fabricated active part of the device are also presented. This combined theoretical–experimental approach opens a new avenue for the design of nanoscale devices with atomic precision. Abstract : Negative differential resistance device concepts require significant modifications to be practical at nanometer dimensions due to undesirable tunneling between the contacts to the device, as well as interference between electronic states. A new multi‐part device structure is proposed and fabricated with atomically precise graphene nanoribbon (GNR) barriers and partially converted GNR (intermediate) segments with a lower band gap.