Organic thin-film transistors for organic light-emitting flat-panel display backplanes

The performance of organic thin-film transistors (OTFT's) has improved significantly in the last several years and it now appears likely that they will find application in low-cost large-area electronic applications. Active-matrix displays are of special interest and integration of OTFT's with organic light-emitting devices (OLED's) in all-organic displays is particularly attractive. The device requirements for active-matrix OLED displays are very similar to those of active-matrix liquid-crystal displays (AMLCD's) and can be satisfied with OTFT's fabricated using stacked pentacene active layers. Such devices have demonstrated field-effect mobility near 1.5 cm2/V·s, on/off current ratio near 108, near-zero threshold voltage, and subthreshold slope less than 1.6 V/decade. These characteristics are similar to those obtained with hydrogenated amorphous silicon (a-Si) devices and such devices would allow the use of polymeric substrates with advantages in weight, ruggedness, and cost compared to glass substrates currently used with a-Si devices in AMLCD's.