Gate voltage dependence of 1/f noise in carbon nanotubes with the different metal contacts

Nano carbon devices are promising for the next generation devices. Recently, a single-layer graphene has also been developed as nano-devices. For the device applications, there are several reasons why we should control the noise. Of course, the reduction of noise is one of strategies for nano devices as the noise might be increases for nano size devices including Si devices. On the other hand, noise is sometimes useful for the enhancements of the small signal operation such as stochastic resonance. In this case, noise can help the operation of the device as transistors. However, for the stochastic resonance devices, noise control is also important for the actual operations. We also reported the gate voltage control of stochastic resonance in carbon nanotubes field effect transistor (CNT-FET). On the other hand, as the device structures, the electrode should fit to the total process of device fabrications. In this paper, we discuss about the metal contact dependence of noise control for CNT-FET. Usually, CNT-FET has special gate voltage dependence with carrier number control of noise in the channel. On the contrary, the thick electrode of Ti/Au can cause the reverse dependence of noise by the gate voltage. In this case, the crossover of the two different noises is important. Thus, the noise properties seem to be also useful for the evaluation of noise in the device structures.