Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 50: HL Poster IV

HL 50.31: Poster

Donnerstag, 15. März 2018, 19:00–21:00, Poster B

Structural and electronic properties of natural graphite — •Ana Champi and Henrique Ferreira — Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170, Santo André, SP, Brazil

In this work, we have studied natural graphite flakes extracted from Brazil mines with high content of rhombohedral phase than artificial graphites like HOPG. We have performed measurements of Raman spectroscopy in many samples and different points on the surface in order to obtain a good statistical characterization. We verified the electrical behavior of the samples through electrical resistance measurements as a function of the temperature, initially the flakes shows extrinsic semiconductor like behavior, followed by persistent metallic behavior in the studied temperature ranges (300K to 500K). We have also studied the effect of the temperature on the Raman spectra, showing a broadening of the characteristic bands of graphite. According to the obtained results, we interpret that the extrinsic semiconductor-like behavior is due to oxygen adsorption at the graphite defects.