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Báo cáo hóa học: " Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy | Giannazzo et al. Nanoscale Research Letters 2011 6 109 http www.nanoscalereslett.eom content 6 1 109 o Nanoscale Research Letters a SpringerOpen Journal NANO REVIEW Open Access Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy Filippo Giannazzo1 Sushant Sonde1 2 Emanuele Rimini1 3 Vito Raineri1 Abstract In this article a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene. The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects vacancies . Electron mean free path is mainly limited by charged impurities in unirradiated graphene whereas an important role is played by lattice vacancies after irradiation. The local density of the charged impurities and vacancies were determined for different irradiated ion fluences. Introduction Graphene a two-dimensional 2D sheet of carbon atoms in a honeycomb lattice attracted the interest of the nanoelectronics scientific community for its remarkable carrier transport properties 1 2 . Ideally in a free-standing graphene sheet without lattice defects and adsorbed impurities charge carriers can exhibit a giant intrinsic mobility 2 and can travel for micrometers without scattering at room temperature. As a matter of fact very high values of mobility 2 X 105 cm2 V-1s-1 and electron mean free path have been observed only in vacuum and at low temperature 5 K in suspended graphene sheets obtained by mechanical exfoliation of highly oriented pyrolytic graphite HOPG 3 . The mobility values measured at room temperature commonly reported in the literature range from approximately 2 to 2 X 104 cm2 V-1s-1 depending on the graphene synthesis methods 1 4 on the kind of substrate on which it is deposited 5 and on the .