tailieunhanh - Nanotechnology Science and Computation Part 10

Tham khảo tài liệu 'nanotechnology science and computation part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Molecular Electronics from Physics to Computing 227 Fig. 2. Schematic illustration of the device structures of a conventional CMOS device and a typical nanodevice. both impurity and lattice vibration. It also leads to distinctly different electrostatic behavior from the planar silicon device which affects both screening and tunneling. 2 The C-C sp2 bonding leaves no dangling bond on the surface. In particular for single-wall carbon nanotubes SWNTs all carbon atoms are surface atoms. CNT electronics are not bound to use SiO2 as an insulator and novel transistor structures like surrounding gate transistors can be adapted. 3 The strong C-C sp2 bonding gives CNTs high mechanical and thermal stability. Current densities 109 A cm2 can be sustained. Several critical issues related to contact doping and scattering remain to be sorted out for further development of CNT-based nanoelectronics. In contrast to silicon MOSFETs the source drain and gate electrodes in MolFETs are made from deposited or lithographically defined metals. The Schottky barriers at the CNT-metal contacts play a significant role in determining the transport characteristics 6 80 150 we can also expect that the Schottky barrier problem will play an increasingly important role as MOS-FETs scale toward the sub-10nm regime since the low-frequency plasmon in the doped source drain region can be removed by using metal electrodes . Due to the Q-1D geometry both the barrier height and barrier shape are important in determining the relative importance of tunneling and thermionic emission across the barrier. The recent observation of ohmic contact using Pd provides a particular challenge 57 58 as the previous theoretical study shows a similar Schottky barrier for Pd and Au that have similar work functions. However the model used assumes only electronic coupling across the interface with fixed atomic structure. Transition metals including both Ti and Pd are known to be chemically active attaching to the CNT surface