Modeling of the temperature dependence of the field-effect mobility in thin film devices of conjugated oligomers

A simple model is proposed for charge carrier transport across grain boundaries with an acceptor-like trap level. Potential wells between the grains are formed due to negatively charged grain boundaries. Based on this model, a variety of temperature dependencies of the charge carrier mobility can be described. Using realistic parameters, this model reproduces very well the measured temperature dependencies of the field-effect mobility in polycrystalline pentacene and oligothiophene thin film devices. Therefore, it seems to be difficult to investigate the intrinsic material properties of organic semiconductors using only polycrystalline field-effect devices, since they may be masked by the effects of traps and grain boundaries.

[1]  Thomas N. Jackson,et al.  Temperature-independent transport in high-mobility pentacene transistors , 1998 .

[2]  F. Baumgartner,et al.  Hall mobility minimum of temperature dependence in polycrystalline silicon , 1998 .

[3]  Sampath Purushothaman,et al.  Field-effect transistors comprising molecular beam deposited α,ω-di-hexyl-hexathienylene and polymeric insulator , 1998 .

[4]  L. Torsi,et al.  CHARGE TRANSPORT IN OLIGOTHIOPHENE FIELD-EFFECT TRANSISTORS , 1998 .

[5]  Stephen C. Moratti,et al.  Bis(dithienothiophene) organic field-effect transistors with a high ON/OFF ratio , 1997 .

[6]  Thomas N. Jackson,et al.  Pentacene-based organic thin-film transistors , 1997 .

[7]  G. Horowitz,et al.  Improved field‐effect mobility in short oligothiophenes: Quaterthiophene and quinquethiophene , 1997 .

[8]  T. Jackson,et al.  Pentacene organic thin-film transistors-molecular ordering and mobility , 1997, IEEE Electron Device Letters.

[9]  A. Dodabalapur,et al.  Intrinsic Transport Properties and Performance Limits of Organic Field-Effect Transistors , 1996, Science.

[10]  Sakaki,et al.  Charge transport in thin films of semiconducting oligothiophenes. , 1995, Physical review. B, Condensed matter.

[11]  S. Hotta,et al.  Crystal structures of oligothiophenes and their relevance to charge transport , 1993 .

[12]  H. Sakaki,et al.  FET characteristics of substituted oligothiophenes with a series of polymerization degrees , 1993 .

[13]  Gilles Horowitz,et al.  An analytical model for organic‐based thin‐film transistors , 1991 .

[14]  Gilles Horowitz,et al.  A field-effect transistor based on conjugated alpha-sexithienyl , 1989 .

[15]  D. Emin.  Lattice Relaxation and Small-Polaron Hopping Motion , 1971 .

[16]  T. Holstein,et al.  Studies of polaron motion: Part II. The “small” polaron , 1959 .

[17]  J. Frenkel,et al.  On Pre-Breakdown Phenomena in Insulators and Electronic Semi-Conductors , 1938 .

[18]  L. Torsi,et al.  Low Temiperature Band Transport in Alpha-Hexathienylene Thinfilm-Transistors , 1995 .