Lecture : 9 Carbon Nanotubes and Carbon Nanotube transistors. S. E. Thompson Fall 2004

Transcription

1 1 Lecture : 9 Carbon Nanotubes and Carbon Nanotube transistors S. E. Thompson Fall 2004

2 Ref. P. Wong, IBM 2

3 Ken David, Intel 3

4 Nanoelectronics Now or Never?" IEDM Evening Panel Discussion, December 14, 4 Session 26: 8:00 p.m. Continental Ballroom 6-9 Moderator: Mark Lundstrom, Purdue University "Nanoelectronics Now or Never?" Traditional 'top-down' microelectronics has become nanoelectronics with device dimensions comparable to those being explored in the new field of ëbottom-up' nano- and molecular electronics. We use the terms, top-down and bottom-up, in a very general sense. Top-down refers to a way of thinking and building that begins at the macro (continuum) scale and pushes to the nanoscale. Bottom-up refers to a way of thinking and building that begins at the atomistic level and builds up to the nanoscale. The top-down approach has already delivered silicon MOSFETs with channel lengths of ~ 5nm, but scaling down device dimensions with commensurate increase in device and system performance is increasingly challenging. Bottom-up technology has demonstrated molecular switches, nanotube and nanowire FET's, NDR and single electron devices, and ultradense memory prototypes. Is bottom-up nanotechnology ready to address the industry's challenges, or is it still long-term research with essentially unpredictable outcomes? This panel will debate the question of what the intersection of top-down and bottom-up electronics will mean to semiconductor technology of the future.

5 Carbon Nanotube Growth 5

6 Reason Carbon Nanotubes are Interesting 6 Fundamental physics and chemistry changes when the dimensions of a solid becomes comparable to one or more of these characteristic lengths, many of which are in the nanometer range. Example: Size of semiconducting material is in the order of the wavelength of the electrons and holes. Electronic structure and transport completely changes

7 Roll Carbon Nanotube from Graphite 7 Ref: Intro to Nanotechnology

8 Constructing Nanotubes from a Graphene Sheet 8 Chiral angle Zigzag 0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 10,0 11,0 12,0 13,0 1,1 1,1 3,1 4,1 5,1 6,1 7,1 8,1 9,1 10,1 11,1 12,1 13,1 Roll-up vector 2,2 3,2 4,2 5,2 6,2 7,2 8,2 9,2 10,2 11,2 12,2 3,3 4,3 5,3 6,3 7,3 8,3 9,3 10,3 11,3 12,3 Armchair 4,4 5,4 6,4 7,4 8,4 9,4 10,4 11,4 5,5 6,5 7,5 8,5 9,5 10,5 11,5 a 1 6,6 7,6 8,6 9,6 10,6 a 2 7,7 8,7 9,7 10,7 8,8 9,8

9 9 Semiconductor nanotubes 2,0 3,1 4,2 5,3 6,4 7,5 8,6 9,7 10,8 11,9 5,0 6,1 7,2 8,3 9,4 10,5 11,6 12,7 8,0 9,1 10,2 11,3 12,4 13,5 11,0 12,1 13,2 14,3 14,0 15,1 1,0 2,1 3,2 4,3 5,4 6,5 7,6 8,7 9,8 10,9 11,10 4,0 5,1 6,2 7,3 8,4 9,5 10,6 11,7 12,8 7,0 8,1 9,2 10,3 11,4 12,5 13,6 10,0 11,1 12,2 13,3 14,4 13,0 14,1 15,2 16,0 10,9 9,8 8,7 7,6 6,5 5,4 10,6 9,5 8,4 12,5 11,4 10,3 9,2 13,3 12,2 11,1 10,8 9,7 8,6 7,5 6,4 11,6 10,5 9,4 8,3 13,5 12,4 11,3 10,2 9,1 13,2 12,1 15,1 zigzag armchair 1.0 nm diameter

10 Some More Properties of Nanotubes 10 1 to 10 nm diameters 10 of um long End capped with half a fullerence molecule Single and multi-wall nanotubes Chirality refers to how the tubes are rolled One-third metallic two-thirds semiconductor Energy gap: 1/(diameter of tube) Diameter of tube increases, bandgap decreases

11 Extension of C 60, C 70, C End closed 11

12 Multi Wall Tubes 12

13 Bandgap of Semiconductor Tube 13

14 s and p Wavefunctions 14 Ref: Intro to Nanotechnology

15 Carbon Nanotubes: Fullfill Requirements For a Logic Device? 15 Non-linear characteristics Power amplification Concatenability Feedback prevention Basic Logic

16 C Ref: Intro to Nanotechnology

17 Closed Network From Other Atoms 17 Ref: Intro to Nanotechnology

18 Si Nano Wires Converted to NiSi 18 Si nanowire Lieber, Nature 2004

19 Si Nano Wire Transistors 19 Lieber, Nature 2004

20 Carbon Nanotubes: Fullfill Requirements For a Logic Device? 20 Non-linear characteristics Power amplification Concatenability Feedback prevention Basic Logic

21 Summary 21

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35 Carbon Nanotube Lectures 35 What are Carbon Nanotubes and Transistors Metrology Used to Measure Nanotubes Mass spectrometer Transmission Electron Microscopy Scanning Microscopy Scanning electron microscope Scanning tunneling microscope Atomic force microscope How nanotubes are grown Carbon Nanotube Electronic Properties Carbon Nanotube State of the Art Transistors Carbon Nanotube Integration Carbon Nanotube Potential Future Applications Nobel Prize winner Prof. Richard Smalley Lecture on Nanotubes

36 References 36 Chapter: Carbon nanotube for data processing

37 What is a Carbon Nanotude Transistor 37

38 Ref: Jing Guo 38

39 Nanotechnology 39 The Principles of Physics, as far as I can see, do not speak against the possibility of Maneuvering things atom by atom. It is not an Attempt to violate any laws; it is something, in Principle, that can be done; but in practice, it Has not been done because we are too big Richard Feynman

40 Nanotechnology History 1959 Plenty of Room at the Bottom Richard Feynman Lecture given to American Physical Society Feynman envisioned Etching lines a few atoms wide Patterning with e-beam Manipulating individual atoms (scanning tunneling microscope) Building circuits on nanometer scale Nanostructures already present in biological systems 40

41 Micro and Nano History 1 Micro and Nano History Scanning tunneling microscope (STM) Heinrich Rohler and Gerd Karl Binning Buckyballs discovered Richard Smalley, Robert Curl, Jr., Harold Kroto 1986 Atomic Force Microscope (AFM) 1991 Carbon Nanotube discovered as part of ERATO program in Japan ( ) Sumio Ijima 1996 NSF commissioned nanoscience and nanotechnology study Recommned National Nanotechnology Initiative 2001 Nanotube logic demonstrated with carbon nanotubes 41

42 What is a Carbon Nanotube? 42 Start with Carbon Graphite C 60 Single Wall Carbon Nanotubes Multi Wall Carbon Nanotubes Carbon Nanotube Transistors

43 Start with Carbon 43 Carbon contains six electrons (1s) 2, 2s, 2px,2py, 2pz 1s quantum number N=1 (2 electrons) N=2, four electrons s orbital spherically symmetric about nucleous p directed charge distribution s and p form chemical bond Ψ = s + λp Solid carbon two main structures Diamond sp degree bonds Graphitic sheet sp degree bonds. Each bond in same plane Graphite s, px, py Sheets held together by weaker van der Waals Forces

44 Discovery of C Soccer ball-like molecule containing 60 carbon atoms Motivated by understanding ligh transmission through interstellar dust Optical extinction: absorption and scattering of light from interstellar dust C60 envisioned by theoretical chemist High powered pulsed laser simulate conditions of hot carbon Prof. Richard Smalley (Rice) observed mass number 720 mass spectrometer (carbon mass #12) Smalley won Nobel prize

45 ATM or STM Used to Determine Chirality 45