Influence of the Structure on Mobility Data

That the main effect of the enhanced conductivity by higher structural order is the enhanced mobility is corroborated by measurements of field effect mobilities (Table 10) [100, 132, 333, 334, 342-346], although field effect mobilities are lower if compared to intrinsic mobilities due to parasitic series resistances in short channel devices [347][348] and channel length shortening [348, 349]. Today thin films can be prepared in which the mobility of a-6T films nearly meets that of single crystals and 

Furthermore newer measurements on highly ordered a-4T and a-5T films [333, 334] exhibit 4 respectively 2 orders of magnitude higher mobilities which are similar to the values of a-6T, although leaky PMMA gates were used instead of Si02. Also better purification of q-8T leads to higher mobilities [100]. 

The field effect mobility may also be decreased by interface states. This is supported by the increase of the field effect mobility by using different insulators [250, 350]. Also drift mobilities extracted from electroluminescence measurements show a thickness dependence pointing to an influence of the interface [351], 

---