Nanotube memory devices

Figure 3.6 Response of PmPV polymer-coated CVD-grown SWNT-FET device to UV light (A- = 365 nm). (A) The source-drain current (/sd) versus the gate voltage (Kg) of the device in air (Ksd = 1 V) at UV-off (blue curves) and UV-on (red curves) conditions. The reversible hysteresis (forward 7sd -reverse 7sd) in the device measured in the range of 20 V (-10 V to +10 V) at the sweep rate of 4 Hz. The inset shows the polymer-coated CVD-grown SWNT-FET device geometry. (B) Current (7sd) versus time response to UV illumination of PmPV-coated SWNT-FET device in air at room temperature (Fq = 4 V, Fsd = 1 V). The inset shows no apparent recovery in the device conductance after 16 h at fixed Fg conditions. Shaded and unshaded regions mark the UV-on and -off periods, respectively. Reprinted (adapted) with permission from Star, A. et al. Nanotube Optoelectronic Memory Devices. Nano Letters, 2004. 4(9) pp. 1587-1591. Copyright (2004) American Chemical Society.

A reduction of the required energy could be reached by the incorporation of conductive fillers such as heat conductive ceramics, carbon black and carbon nanotubes [103-105] as these materials allowed a better heat distribution between the heat source and the shape-memory devices. At the same time the incorporation of particles influenced the mechanical properties increased stiffness and recoverable strain levels could be reached by the incorporation of microscale particles [106, 107], while the usage of nanoscale particles enhanced stiffness and recoverable strain levels even more [108, 109]. When nanoscale particles are used to improve the photothermal effect and to enhance the mechanical properties, the molecular structure of the particles has to be considered. An inconsistent behavior in mechanical properties was observed by the reinforcement of polyesterurethanes with carbon nanotubes or carbon black or silicon carbide of similar size [3, 110]. While carbon black reinforced materials showed limited Ri around 25-30%, in carbon-nanotube reinforced polymers shape-recovery stresses increased and R s of almost 100% could be determined [110]. A synergism between the anisotropic carbon nanotubes and the crystallizing polyurethane switching segments was proposed as a possible... 

Yu, W.J., Chae, S.H., Lee, S.Y., Duong, Di., Lee, Y.H., 2011a. Ultra-transparent, flexible single-waUed carbon nanotube non-volatile memory device with an oxygen-decorated graphene electrode. Advanced Materials 23, 1889—1893. 

The nanotechnology report issued in February 2004 by the UK Royal Society makes the general observation that Electrical transport properties across interfaces remain poorly understood in terms of science/predictive capability. This affects all nanomaterials . This observation most keenly summarizes the present state of play for Gbit level random access memories (RAMs), and it is our view that the electrode interface issues may dominate the device physics. Within the nanotech roadmap , high-dielectric ( high-K ) materials are strongly emphasized, as are nanotubes and new interconnects. 

Semiconductor A generic term for a device that controls electrical signals. It specifically refers to a material (such as silicon, germanium or gallium arsenide) that can be altered either to conduct electrical current or to block its passage. Carbon nanotubes may eventually be used as semiconductors. Semiconductors are partly responsible for the miniaturization of modem electronic devices, as they are vital components in computer memory and processor chips. The manufacture of semiconductors is carried out by small firms, and by industry giants such as Intel and Advanced Micro Devices. 

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