Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 33: Surface Modification
DS 33.2: Vortrag
Donnerstag, 28. Februar 2008, 15:00–15:15, H 2032
Field effect mobility and carrier concentration of graphitized polymer surfaces — •Y. Koval, I. Lazareva, and P. Müller — Institut für Physik der Kondensierten Materie, Universität Erlangen-Nürnberg, Erwin-Rommel Str. 1, 91058 Erlangen, Germany
Recently we have shown that surfaces of various polymers can be graphitized by low-energy ion irradiation [1]. Because of the low energy of ions, the thickness of the graphitized layers is less than 10 nm. By varying the irradiation conditions, the conductivity of the graphitized layers can be changed between 10−5 and 200 S/cm. This rather high conductivity makes graphitized layers interesting for several applications in microelectronics. We present our results of graphitized polyimide surfaces. We have found that the conductivity of low conducting samples can be described by variable range hopping, while highly conducting samples show a semi-metallic behavior. Field effect mobility and carrier concentration were determined for both low and highly conducting samples. It is worth to note that highly conducting surfaces show a field effect mobility as high as 5 cm2/Vs. It was found that the rise of conductivity is caused by a simultaneous increase of the carrier concentration and the mobility of charge carriers. Moreover, a correlation between carrier concentration and mobility was found.
[1] I. Lazareva, Y. Koval, M. Alam, S. Strömsdörfer, P. Müller, Appl. Phys. Lett. 90, 262108 (2007)