Fabrication of field-effect transistor devices with fullerodendron by solution process

Fabrication of field‐effect transistor devices with fullerene related materials

“…Therefore, the µ value determined from the saturation region is consistent with that from linear region, guaranteeing the validity of µ value of this FET device. Figure 2(c) shows temperature dependence of µ value from 190 to 350 K. The µ value increases exponentially with an increase in temperature from 250 to 300 K, and it rapidly decreases above 300 K. The drastic decrease in µ above 300 K is also observed in the fullerodendron (II) FET device [7]. The µ-T plot shows that the channel conduction of fullerodendron (I) films follows thermally-activated hopping-transport model (µ ~ exp -E a /k B T) above 240 K. The activation energy E a was determined to be 25 meV from ln µ -1/T plot at 250-300 K as shown in Fig.…”

“…In the same way, the fullerodendron (II) FET devices on the PVA/PET and PVP/PET substrates were also fabricated and the FET properties were studied. The values of µ and V T were 1.7 × 10 -3 cm 2 V -1 s -1 and -110 V, respectively, in the FET device with PVA gate insulator [7], while those of µ and V T were determined to be 4.6 × 10 -5 cm 2 V -1 s -1 and -92 V, respectively, in the FET device with PVP gate insulator. All FET devices with polymer insulators on PET substrates showed normally-on FET properties.…”

“…Recently, we have fabricated a solution-processed FET device based on fullerodendron molecule with two-times repeated dendron units, fullerodendron (II) ( Fig. 1(a)), and it showed n-channel normally-off like FET properties with the field-effect mobility µ of 1.4 × 10 -3 cm 2 V -1 s -1 [7]; the value is relatively high among solution-processed FET devices. Here, it should be noted that the formation of π-conduction channel path between the C 60 moieties is a key point for a realization of higher µ value.…”

Transport properties of field-effect transistor with Langmuir-Blodgett films of C60 dendrimer and estimation of impurity levels

“…2͑b͔͒. No FET properties were observed in the FET device with the L of 30 m, suggesting that the ordered region in the LB films is still smaller than 30 m, while the FET properties with spin-coated films could be observed at L =30 m. 5 In the spin-coated films, the conduction path was easily formed even at the L of 30 m because of the thicker films ͑ϳ1 m͒ than the LB films ͑ϳ15 nm͒. The on-off ratio reached 10 7 in the LB film FET.…”

“…2 Recently, we have fabricated the FET devices with the spin-coated films of C 60 dendrimer ͓Fig. 1͑a͔͒ developed by Takaguchi and co-workers, 3,4 and the value was 1.4 ϫ 10 −3 cm 2 V −1 s −1 at 300 K 5 . The channel conduction is based on network through the C 60 moieties.…”