Molecular and Cellular Surface Imaging Facility

The goal of the MOCSI Facility (known informally as the Surface Facility) is to provide tools that can generate images of surface or near-surface characteristics, such as topography or electronic structure, at length scales from microns down to nanometers in environments ranging from ultra high vacuum to fluid. The primary tools are specialized scanning probe microscopes (SPMs) that complement the capabilities of the standard SPMs found in the CCMR Materials Facilities and in other Cornell centers. Vacuum surface processing equipment, which can be configured according to users’ needs, is also available for preparing samples prior to characterization.

	Manager Prof. Christopher “Kit” Umbach, MS&E 607.255.7339 umbach@ccmr.cornell.edu	Faculty Advisor Prof. Dan Luo, B&EE dl79@cornell.edu
	Main Location: SB-30 Bard Hall

Instrumentation

Confocal Raman Microscopy
Specifications

• Reflection Raman microscopy enables chemical identification of elements and compounds with a spatial resolution of ~1 µm. Raman shifts within 150 cm-¹ of the excitation frequency can be measured at excitation wavelengths of either 488 nm or 785 nm with a spectral resolution of ~0.1 cm-¹.
• Spatial maps of Raman intensity over an area 70 µm x 70 µm can be made using a Nanonics scan stage.
• Specialized applications: a) polarized Raman; b) photoluminescence; c) simultaneous Raman/AFM.

Equipment

• NSOM: Nanonics MV1000 or MV2000 interfaced with an Olympus BXFM focusing unit, configurable as either an upright or inverted microscope, using a 50x long-working distance objective.
• Infrared digital cameral for IR laser adjustment and sample or probe positioning.
• Excitation lasers: a) Nd:YAG (532 nm); b) multi-line single-mode Ar-ion gas laser (lines from 457 to 514 nm) multi-line single mode Ar-Kr ion gas laser (lines from 476 to 676 nm).

Near-Field Scanning Optical Microscopy (NSOM)
Specifications

• A nanoscale aperture at the end of a scanning probe collects or excites optical signals with sub-wavelength spatial resolution, while simultaneously collecting topographical data in AFM mode.
• Scan area is 70 µm x 70 µm with a vertical range of 70 µm. NSOM resolution is ~50 to 200 nm (dependent on aperture size). AFM lateral resolution is ~5 nm to 10 nm; vertical resolution is ~1 nm.
• Specialized applications: a) near-field fluorescence imaging using an avalanche photodiode (APD) for low-intensity light detection b) far-field stage-scanned confocal mode using a pinhole placed in front of the APD; c) imaging in fluid; d) tip-enhanced Raman scattering (TERS).

Equipment

• A nanoscale aperture at the end of a scanning probe collects or excites optical signals with sub-wavelength spatial resolution, while simultaneously collecting topographical data in AFM mode.
• Scan area is 70 µm x 70 µm with a vertical range of 70 µm. NSOM resolution is ~50 to 200 nm (dependent on aperture size). AFM lateral resolution is ~5 nm to 10 nm; vertical resolution is ~1 nm.
• Specialized applications: a) near-field fluorescence imaging using an avalanche photodiode (APD) for low-intensity light detection b) far-field stage-scanned confocal mode using a pinhole placed in front of the APD; c) imaging in fluid; d) tip-enhanced Raman scattering (TERS).

Noncontact atomic force microscope image of ripples in a glass surface induced by ion bombardment.

Ultrahigh Vacuum Scanning Probe Microscopy
Specifications

• Atomic force microscopy in vacuum up to sample temperatures of 400°C: contact, tapping, noncontact, lateral force, for topographic imaging at high spatial resolution(<5 nm).
• Scanning tunneling microscopy (STM) in vacuum up to sample temperatures of 500°C and tunnel currents below 1 picoampere: atomic-scale topography and spatially resolved electron spectroscopy of conducting materials.
• Special applications: a) electron beam irradiation or laser beam irradiation (He:Cd 325 nm) of the sample while on
  the AFM/STM stage; b) a UHV processing chamber for deposition of thin-films, sputter cleaning, and high-
  temperature heating (up to 1200°C) prior to imaging.

Equipment

• JEOL JSPM 4500 ultrahigh vacuum scanning probe microscope.

Scanning tunneling microscope image of the 7x7 reconstruction of the silicon surface: the bright circular shapes are individual atoms.