Temperature-dependent carrier mobility and threshold voltage of field-effect transistors with tetracene single crystals

摘要

Temperature-dependent carrier mobility and threshold voltage of organic field effect transistors (OFET) with tetracene single crystals pressed onto a SiO_2/Si substrate were measured in the temperature range between 80 and 300 K. The mobility increases with decreasing temperature, reaching a maximum at 240 K. Further reduction of temperature leads to the decrease of the mobility, before leveling out below 140 K. We find that the critical temperature is strongly correlated with that of the threshold voltage which depends on the number of carriers captured in deep traps. From these temperature-dependent OFET characteristics, a carrier transport model including shallow and deep traps is suggested.