chapter  14
Nanofabrication andNanocharacterizationUsing Near-Field Optics
Pages 24

In this chapter, techniques and platforms to fabricate and characterize nanostructures using optical approaches based on tip-enhanced near-eld effects are introduced. The background of these techniques is reviewed. The details of a nano-Raman spectrometer and imaging system developed for characterizing materials and devices at nanoscales and a laser-assisted scanning tunneling microscope (LASTM) developed for performing surface nanostructuring are presented. Both the

14.1 Introduction .......................................................................................................................... 378 14.1.1 Background ............................................................................................................... 378 14.1.2 Near-Field Optics: The Path to Achieving Nanometer Optical Resolutions ............ 379 14.1.3 Nano-Raman Spectroscopy: A Unique Tool for Identifying Chemicals at

Nanoscales ................................................................................................................ 381 14.1.4 Surface Nanostructuring: The Way to Build Nanodevices ...................................... 381

14.2 Development of a Nano-Raman Spectrometer Using Tip-Enhanced Near-Field Effects .... 383 14.2.1 Near Fields Achieved by Metallic Tips .................................................................... 383 14.2.2 System Setup of a Nano-Raman Spectrometer ........................................................384 14.2.3 Performance of the Developed Nano-Raman Spectrometer .................................... 385 14.2.4 Characterization of Single-Walled Carbon Nanotubes (SWCNTs) .......................... 387

14.3 Enhanced Raman Spectroscopy by Combining a Metallic Tip with Surface Nanostructures ...................................................................................................................... 388 14.3.1 Near Fields Achieved by Combining a Metallic Tip with Surface

Nanostructures .......................................................................................................... 388 14.3.2 Enhanced Raman Spectra of Silicon Substrates Covered with Nanostructures....... 389

14.4 Fabrication of Nanostructures with High Electrical Conductivity on Silicon Substrates Using a Laser-Assisted Scanning Tunneling Microscope (LASTM) ................................... 391 14.4.1 System Setup of a Laser-Assisted Scanning Tunneling Microscope (LASTM) ...... 391 14.4.2 Impact of Laser Fluence and Number of Pulses on Nanostructures ........................ 391 14.4.3 Characterization of Nanostructures Using Scanning Tunneling

Spectroscopy (STS) .................................................................................................. 392 14.4.4 Mechanism Investigation of Surface Nanostructuring on Silicon Substrates .......... 394

14.5 Conclusions ........................................................................................................................... 396 Questions ........................................................................................................................................ 397 Acknowledgments .......................................................................................................................... 397 About the Contributing Authors ..................................................................................................... 397 References ...................................................................................................................................... 398

nano-Raman spectrometer and LASTM processes feature spatial resolutions of ~30 nm, much beyond the optical diffraction limit.