Browse Prior Art Database

Identification of Molecular Species at Surfaces With High Spatial Resolution

IP.com Disclosure Number: IPCOM000120085D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Clabes, JG: AUTHOR [+3]

Abstract

Disclosed is a technique for the detection and identification of adsorbates and residues on surfaces with very high spatial resolution using either scanning tunneling microscopy (STM) or atomic force microscopy (AFM) in conjunction with infrared spectroscopy.

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This is the abbreviated version, containing approximately 52% of the total text.

Identification of Molecular Species at Surfaces With High Spatial
Resolution

      Disclosed is a technique for the detection and
identification of adsorbates and residues on surfaces with very high
spatial resolution using either scanning tunneling microscopy (STM)
or atomic force microscopy (AFM) in conjunction with infrared
spectroscopy.

      The imaging capabilities of STM or AFM of surfaces and adlayers
with atomic resolution can be extended to facilitate information
about the presence, distribution and orientation of particular
adsorbates and organic residues by employing a tunable monochromatic
infrared laser.  The selective absorption into specific vibrational
modes of the adlayer results in a wavelength dependent modulation of
the tunneling or the interaction force conditions which will cause a
change of the tunneling current (STM) or the attractive force (AFM).

      The technique involves illumination of the tunnel junction with
infrared radiation having a wavelength matching a vibrational
absorption band of the adsorbed molecule.  In the STM, excitation of
a molecular vibrational mode is expected to lead to changes in the
tunneling current, either as a result of the increased energy of the
molecule while excited, or else as a result of the heat dissipated
into the sample when the molecules become vibrationally relaxed, or
possibly through other mechanisms. In the AFM, vibrational excitation
is also expected to lead to changes in the forces between the sam...