High Performance Vertical-Type Organic Transistors And Organic Light Emitting Transistors

We have fabricated organic static induction transistor (SIT) and organic light emitting transistor (OLET) combining SIT with organic light emitting diode (OLED). SIT and OLET have a grid-type Al gate electrode that was formed using a shadow evaporation mask in the organic semiconductor layers. The effective electrode area of SIT and OLET is approximately 4 mm
²
. By optimizing the device structure, excellent performances of SIT and OLET were obtained. The drain-source current (I
_DS
) at a constant drain-source voltage (V
_DS
) decreases with increasing the gate voltage (V
_G
). The current is controlled by relatively small V
_G
(-10 V) and a typical SIT characteristic is obtained in the OLET. The luminance of OLET also varies corresponding to the I-V characteristics. The maximum current and luminance values were approximately 10 mA and 10,000 cd/m
²
, respectively. We have also investigated the electrical characteristics of organic SITs having several gate gaps. The organic SIT with gate gap (D
_g
) less than 200 nm have much smaller off currents and much larger on/off ratios.