Contentslistsavailableat ScienceDirect Microelectronic Engineering journal homepage: www.elsevier.com/locate/mee Research paper Efectof E-beamirradiationongraphenesandwichedbetweenh-BNlayers M.W.Iqbal a, ⁎ ,G.Hussain a ,M.A.Kamran b ,I.Aslam c ,T.Alharbi b ,S.Azam a ,A.Majid b ,S.Razzaq a a Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, 14 Ali Road, Lahore, Pakistan b Department of Physics, College of Science, Majmaah University, P.O. Box no. 1712, Al-Zulfi 11932, Saudi Arabia c Department of Basic Sciences& Humanities, University of Engineering and Technology Lahore, Narowal campus, Pakistan ARTICLEINFO Keywords: Graphene Boron nitride Sandwiched structure Raman spectra Electrical transport Protection E-beam irradiation ABSTRACT The potential of graphene for electronic applications originates owing to its exceptional room temperature carrier mobility. However, during the fabrication of electronic devices like feld-efect transistors graphene is exposed to external environment that afects its carrier mobility. Also, the formation of dangling bonds at Si/ SiO 2 interface further degrades the mobility of graphene and hence infuence the performance of graphene devices. In order to protect graphene from environmental conditions and preserve its fundamental electrical propertiesinsuchdevices,heregrapheneissandwichedbetweenhBNlayers(i.e.hBN/Graphene/hBN)andthen theefectofe-beamirradiationongraphenestructureisstudied.Toinvestigatestructuraldisorderingraphene, Raman analysis was carried out which revealed no defects in graphene even for a high dose of e-beam irra- diation. The electrical and magneto-transport measurements further confrmed the stability of these e-beam irradiatedhBN-passivatedgraphenedevicestherebydemonstratingamobilityof16,638cm 2 /VsandQuantum Hallplateausat9T,respectively.Furthermore,diferentdevicescomprisingGraphene/SiO 2 ,Graphene/hBNand hBN/Graphene/hBN are studied for the interface analysis, which after e-beam irradiation revealed no defects andcontaminationsattheinterfacesbetweenhBNandgraphene. 1. Introduction The unique electrical features of graphene have given rise to pro- digious applications in electronics, optoelectronics, spintronics and condensed matter physics [1–4]. Graphene is an auspicious material due to its extraordinary charge carrier mobility at room temperature [4–7]. A mobility of approximately 200,000cm 2 /Vs was reported for suspended single layer graphene [8,9]. However, the value is highly reducedwhenitissupportedonasubstrate[8–12].Becauseofthevery lowthicknessofgraphene(singlelayerofgraphite),everyatomofthe structure is bared and exposed to external atmosphere that makes it extremely subtle to the local vicinity [13,14]. For instance while fab- ricatingafeld-efecttransistor(FET),grapheneistransferredontheSi/ SiO 2 substrate that may result in dangling bonds at the interface [15,16].Aftertransferringgrapheneonthesubstrate,theuppersurface of graphene is still open to environmental conditions [16,17]. There- fore, there are very high chances of contaminations, charge impurity scatteringandsurfaceunevennessbyusingtheconventionalfabrication techniquesforgraphenedevices[18,19].Thesefactorshighlyinfuence thestructuralandelectronictransportcharacteristicsofgraphenebased FETs[12].Therefore,supportinggrapheneonasuitablesubstrateand protecting graphene from environmental efects is very essential for high technological applications. Many eforts have been made to sub- stitutetoSi/SiO 2 withasuitablesubstrate,buteachtimesubstratesin the form of oxides are remained to be problematical [16,18–20]. For thatreason,anoxidefreesubstrateistheneedoftimefortheformation ofsmoothinterface.Inthisregard,hexagonalboron-nitride(hBN)asa substrate could be the best possible substitute to oxide substrates be- causeofitslayeredstructureanditsinactivenaturehavingnodangling bonds [21,22]. It has negligible surface infuence in graphene devices by forming a smooth interface with very low concentration of charge contaminations [23–25].Inaddition,theinsulatingnature(highband gap)andsmoothsurfaceofhBNmakethismaterialappropriateasdi- electric and as a tremendous substrate [26,27]. The mechanically ex- foliated hBN is generally in tiny pieces and is applicable only for practical Lab purposes [28]. The large-area and fnest growth ofhBN sheet for single layer or a few layers is essential for wide-range elec- tronic industry. For this purpose, chemical vapor deposition (CVD) is commonlyusedforobtaininghBNandother2Dmaterials[29–31]. Here, we investigate the efect of e-beam irradiation on diferent graphene samples (Graphene/SiO 2 , Graphene/hBN and hBN/ Graphene/hBN). Graphene is incorporated between hBN layers; the bottom hBN layer is used as a substrate while the top hBN layer pro- videsshieldingagainsttheenvironment.Sinceitisreportedearlierthat https://doi.org/10.1016/j.mee.2019.111044 Received1December2018;Receivedinrevisedform10June2019 ⁎ Corresponding author. E-mail address: waqas.iqbal@riphah.edu.pk (M.W. Iqbal). Microelectronic Engineering 216 (2019) 111044 Available online 14 June 2019 0167-9317/ © 2019 Elsevier B.V. All rights reserved. T