35 research outputs found

    Combined Ultra High Vacuum Raman and Electronic Transport Characterization of Large Area Graphene on SiO2

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    An original experimental setup which allows for simultaneous sample characterization by Raman spectroscopy and electronic tranport in ultra-high vacuum at low temperatures is presented. We show the applicability of this setup for the case of graphene that is transferred from an Ir(111) single crystal onto SiO2. The transfer of graphene is carried out using a water-promoted electrochemical bubbling technique which is applied to graphene/Ir for the first time. The characterization prior to the transfer includes electron diffraction, photoemission spectroscopy and Raman spectroscopy using ultraviolet excitation. Following the transfer procedure, the graphene layer is electrically contacted and mounted onto a special sample carrier. This carrier allows for combined Raman and transport measurements inside an ultra high vacuum (UHV) system. UHV Raman mapping reveals a large area homogeneous graphene quality over several mm(2) characterized by a D/G intensity ratio less than 0.1. UHV electrical characterization of transferred graphene in a field effect transistor geometry yields a carrier mobility of 675 cm(2) V-1 s(-1). Upon alkali metal doping in UHV conditions using a Cs getter, a decrease of the 4-point resistance from above 2500 omega to below 10 omega is observed. The presented approach paves the way for future combined UHV Raman and transport characterization of two-dimensional materials that are doped into superconducting or charge-density-wave ground states

    Facilitating access to further languages: trialling materials combining parallel texts with reflective learning

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    This article reports on the practitioner research conducted by the English participants in a European Co-operation Programme project entitled Lateral Language Learning. The project was based on the belief that there is much that teachers of a first foreign language can do to prepare heir students to access other languages in the future, and, starting from this premiss, it aimed to develop resources for teachers to use in the classroom. In the English context, a college of further education, the researchers investigated the use of parallel texts within a reflective learning environment. An intitial set of materials using parallel texts in English, Spanish and Portuguese was devised and trialled with four students of A Level Spanish in order to explore how learners could use a parallel text in a related unknown language to identify rules or patterns of correlation and then use this knowledge to access the unknown language. From their observations and evaluation of the students' performance, the researchers drew up a set of principles to inform the design of a second set of aterials. These materials are offered as the basis for a second cycle of practitioner research, to be undertaken by teachers in their own teaching context, and are suitable for use with students learning any foreign language
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