Threshold-Voltage-Shift Mechanism in Pentacene Field Effect Transistors Caused by Photoirradiation

Abstract

The mechanism of the photoinduced threshold voltage shift (ÁV T ) has been studied. We present clear evidence for electron trapping in the pentacene/SiO 2 interface region, which plays a significant role in device instability. A model of ÁV T and hysteresis due to the electron trapping in the pentacene/SiO 2 interface region is proposed on the basis of the experimental results of bias stressing under light. The deeper states in the pentacene forbidden gap are involved in the electron trapping by increasing the reverse bias under the irradiated condition. This results in the further positive shift of V T . In addition, it has been found that the trapped electron lifetime is well described by two time constants, which are thought to be associated with different trapping energy levels in the forbidden gap states of pentacene.

Giant phototransistor response in dithienyltetrathiafulvalene derivatives

“…Single-crystal transistors of thiophene-fused tetrathiafulvalene (DTTTF, Scheme 1) show as high performance as the mobility of 1.4 cm 2 V À1 s À1 , 7 and a signicant photoresponse has been reported. 15 Several other organic semiconductors, including unsubstituted TTF, 16 have been known to show remarkable photoresponse in the transistors, [17][18][19][20][21][22][23][24][25][26][27][28] and are expected to be used as light sensors and optoelectronic memory devices. The threshold voltage shi in materials such as pentacene is, however, less than 20 V. [23][24][25][26] By contrast, a large threshold shi is characteristic of compounds with thiophene units.…”

Organic Field-Effect Transistor/Memory Devices with Pentacene/Polydiacetylene Composite Film As Active Channel Material: A Morphology Dependence Study

“…The ability of polyPDA to trap either holes or electrons is important in expanding the memory window. This characteristics also suggest that the charge trapping occurs at the interfacial region rather than in the pentacene layer, because hysteresis due to traps in the semiconductor layer is not sensitive to gate bias change (4,38). The trapping/detrapping behavior also depends on the sweeping rate.…”

Morphology, Structure, and Dynamics of Pentacene Thin Films and Their Nanocomposites with [C2C1im][NTf2] and [C2C1im][OTF] Ionic Liquids

“…[39,40] From quantum chemical calculations or UV-Vis experiments in solution, some authors have estimated values higher than 2 eV as the optical band gap of pentacene molecules. [39][40][41][42] In some cases, these values have been adopted for many research groups as the band gap for pentacene films, which is a clear overestimation. [41] In fact, contrary to most organic semiconductors, [37] pentacene has a significantly distinct optical band gap in the thin-film state or when dispersed in solution.…”

“…[39][40][41][42] In some cases, these values have been adopted for many research groups as the band gap for pentacene films, which is a clear overestimation. [41] In fact, contrary to most organic semiconductors, [37] pentacene has a significantly distinct optical band gap in the thin-film state or when dispersed in solution. For instance, an optical band gap of 2.07 eV can be found for a diluted solution of pentacene in 1,2-dichlorobenzene.…”