Research on nanodevices and logic circuits composed of nanomaterials by proton irradiation

The studies on the effects of irradiation by high energetic particles such as electron, ion, and proton have received much attention for potential modification of the structural and electronic properties. Such irradiation on the CNTs can introduce structural defects, and the effects of electron and heavy ion, gamma irradiation on CNTs in the electronic, chemical, and mechanical properties have been studied. Effects of different kinds of irradiation on carbon nanotubes and nanowires are of interest from two main points of view. It provides a way to modify the physical (including electronic) and chemical properties by introducing structural modifications on the surface of them. It allows to investigate the effect on one-dimensiosional (1D) nanostructure-based materials exposed by high energetic irradiation which is similar condition as space. In our study, p-type single-walled carbon nanotubes (SWNTs) and n-type ZnO nanowires with excellent and reliable electrical properties have been used for a complementary circuit design such as a complementary inverter, NOR and NAND logic gates, and a static random-access memory (SRAM) cell with operation and/or diodes. Our hybrid complementary devices can be configured in an efficient circuit architecture to decrease the power dissipation and to increase logic performance without additional compensation circuits. Recently, we have demonstrated that SWNT FETs show a high tolerance against proton radiation, while the electrical characteristics of ZnO nanowire FETs are sensitively influenced by the surface trap states at the interface between the ZnO nanowires and dielectric layer. Here, we report a new layout of predictable and controllable complementary logic circuits based on hybrid nanodevices comprising p-channel SWNT and n-channel ZnO nanowire transistors, providing a hybrid approach to combine advantageous characteristic functions for the modulation of the current and operating voltage in transistors through proton radiation-generated charges, which allow a simple way to design favorable logic circuits. Accelerated proton beams were generated using a MC-50 cyclotron. The beam diameter was ∼6 cm, its uniformity was ∼90%, and the average beam current was 10 nA. In our study, the proton beam energy was 10 MeV and the total fluence of proton beam was 1 x 1011 or 1 x 1012 cm-2, corresponding to a proton beam irradiation time of 600 to 6000 s, respectively