Pentacene TFT Uniformity

A uniformity test array consisting of 105 TFTs (W/L = 200/20 pm) was included on the edge of the backplane design the most important properties, field-effect mobilities and threshold voltages, are plotted in Fig. 15.13. The statistics on threshold voltage show the mean value was 13.7 V, the standard deviation 0.78 V, and 

Although the data here show we can achieve relatively uniform TFT performance, it is still not good enough for a display application, so a compensation circuit would be needed in the pixel design. Threshold voltage stability and uniformity, together, form perhaps the most risky feature of organic TFT backplanes for OLEDs. 

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