Organic Transistors: Two-Dimensional Transport and Improved Electrical Characteristics

Science  14 Apr 1995:
Vol. 268, Issue 5208, pp. 270-271
DOI: 10.1126/science.268.5208.270


The thiophene oligomer α-hexathienylene (α-6T) has been successfully used as the active semiconducting material in thin-film transistors. Field-induced conductivity in thin-film transistors with α-6T active layers occurs only near the interfacial plane, whereas the residual conductivity caused by unintentional doping scales with the thickness of the layer. The two-dimensional nature of the field-induced conductivity is due not to any anisotropy in transport with respect to any molecular axis but to interface effects. Optimized methods of device fabrication have resulted in high field-effect mobilities and on/off current ratios of > 106. The current densities and switching speeds are good enough to allow consideration of these devices in practical large-area electronic circuits.