Characterization of surface graphitic electrodes made by excimer laser on CVD diamond

• Published in: Diamond and related materials Vol. 65; pp. 137 - 143
• Main Authors: De Feudis, M., Caricato, A.P., Chiodini, G., Martino, M., Alemanno, E., Maruccio, G., Monteduro, A.G., Ossi, P.M., Perrino, R., Spagnolo, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2016
• Subjects: Atomic structure; Carbon; Detectors; Diamond detectors; Diamond graphitization; Diamonds; Electrodes; Excimer laser; Excimer lasers; Graphitic electrodes; Graphitic structure; Transmission lines; Diamond detectors
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2016.03.003

In this work graphitic structures were fabricated on high quality polycrystalline CVD diamond by using a UV laser beam (λ=193nm). Two different kinds of structures were realized on diamond to study the evolution from diamond to graphite at different irradiation conditions (spot like structures) and to study their electrical transport properties (strip like structures). The graphitic structures were characterized structurally and morphologically by micro-Raman spectroscopy and atomic force microscopy. The electrical properties were evaluated using the transmission line model. Finally, a full carbon detector was built and tested showing good nuclear detection properties.
When a diamond graphitization process is induced, for example by excimer laser which irradiates the diamond surface, two phenomena occur: diamond graphititization and graphite ablation. The figure shows the physical evolution of the average height of the graphitic spots obtained after laser-diamond interaction, at laser fluence of 5J/cm2, with respect to the number of pulses. The measurements were obtained by AFM investigations (zero level refers flat unirradiated diamond surface). For one and two pulses it dominates a swelling phenomenon which represents the diamond graphitization process (the swelling is due to different mass density between diamond and graphite phases), while for four and eight pulses the graphite ablation dominates generating crates with increasing depth. [Display omitted]
•The physical evolution of the diamond graphitization process was studied.•The characterizations of graphitization and ablation processes of diamond were made by AFM and micro-Raman investigations.•The realization and optimization of ohmic graphitic contacts on diamond surface were done.•The response of full carbon detector to an ionizing particle and estimation of its CCE were reported.