Voltage-induced infrared spectra from the organic field-effect transistor based on N,N′-bis(3-methylphenyl)- N,N′-diphenyl-1,1′- biphenyl-4,4′-diamine (TPD)

The field-effect transistor fabricated with N,N′-bis(3-methylphenyl)- N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (TPD) on a silicon substrate has shown a p-channel organic field-effect transistor (OFET) operating in the accumulation mode. The hole mobility in the TPD layer has been obtained to be 7.2 × 10 -4 cm 2 V -1 s -1 . Gate-voltage-induced infrared absorption from the OFET has been measured in the transmission-absorption configuration by the FT-IR difference-spectrum method. The observed spectra depend on the gate voltage applied. The vibrational Stark effect and the bands originating from the carriers injected into the TPD layer have been observed.