Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 25: Organische Halbleiter II

HL 25.6: Talk

Tuesday, March 25, 2003, 16:30–16:45, BEY/81

Temperature dependence of the field-effect mobility of α,α-dihexylquaterthiophene (DH4T). — •M. Leufgen¹, T. Muck¹, A. Lebib¹, G. Schmidt¹, V. Wagner², J. Geurts¹, and L.W. Molenkamp¹ — ¹Physikalisches Institut, Experimentelle Physik III, Universität Würzburg, Am Hubland, D-97074 Würzburg — ²International University Bremen, Campus Ring 8, D-28759 Bremen

Organic field-effect transistors offer a large field of semiconductor applications e.g. low-cost, large area, transparent and flexible electronics. DH4T is a highly ordering p-type organic semiconductor showing high field-effect mobility in thin film transistors (TFTs), if vacuum-deposited. Moreover, the solubility in many solvents offers the possibility of low-cost spin-coating deposition processes. We prepared TFTs with channel length in the µ m scale using oxidized highly doped n-type silicon wafers with gold contacts made by photo lithography and subsequent vacuum deposition of DH4T (layer thickness >10nm) as active organic layer. We report the temperature dependence of the field-effect mobility of different DH4T TFTs, derived from transfer characteristics measured in the range T=200K to T=345K by a HP4145B semiconductor parameter analyzer. The results show a thermally activated transport mechanism. We discuss them with existing models and also deal with the effects of after-deposition treatment.