Scanning voltage microscopy

Scanning voltage microscopy (SVM) -- sometimes also called nanopotentiometry -- is a scientific experimental technique based on atomic force microscopy. A conductive probe, usually only a few nanometers wide at the tip, is placed in full contact with an operational electronic or optoelectronic sample. By connecting the probe to a high-impedance voltmeter and rastering over the sample's surface, a map of the electric potential can be acquired. SVM is generally nondestructive to the sample although some damage may occur to the sample or the probe if the pressure required to maintain good electrical contact is too high. If the input impedance of the voltmeter is sufficiently large, the SVM probe should not perturb the operation of the operational sample.

SVM is particularly well suited to analyzing microelectronic devices (such as transistors or diodes) or quantum electronic devices (such as quantum well diode lasers) directly because nanometer spatial resolution is possible. SVM can also be used to verify theoretical simulation of complex electronic devices.

For example, the potential profile across the quantum well structure of a diode laser can be mapped and analyzed; such a profile could indicate the electron and hole distributions where light is generated and could lead to improved laser designs.

In a similar technique, Scanning gate microscopy (SGM), the probe is oscillated at some natural frequency some fixed distance above the sample with an applied voltage relative to the sample. The image is constructed from the X,Y position of the probe and the conductance of the sample, with no significant current passing through the probe, which acts as a local gate. The image is interpreted as a map of the sample's sensitivity to gate voltage. A lock-in amplifier aids noise reduction by filtering through only the amplitude oscillations that match the probe's vibration frequency. Applications include imaging defect sites in carbon nanotubes and doping profiles in nanowires.



Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Scanning probe microscopy — Part of a series of articles on Nanotechnology …   Wikipedia

  • Scanning capacitance microscopy — (SCM) is a variety of scanning probe microscopy in which a narrow probe electrode is held just above the surface of a sample and scanned across the sample. SCM characterizes the surface of the sample using information obtained from the change in… …   Wikipedia

  • Spin polarized scanning tunneling microscopy — (SP STM) is a specialized application of scanning tunneling microscopy (STM) that can provide detailed information of magentic phenomena on the single atom scale additional to the atomic topology gained with STM. SP STM was developed by Roland… …   Wikipedia

  • Scanning tunneling spectroscopy — (STS) is a powerful experimental technique in scanning tunneling microscopy (STM) that uses a scanning tunneling microscope (STM) to probe the local density of electronic states (LDOS) and band gap of surfaces and materials on surfaces at the… …   Wikipedia

  • Scanning tunneling microscope — Image of reconstruction on a clean Gold(100) surface …   Wikipedia

  • Scanning electron microscope — These pollen grains taken on an SEM show the characteristic depth of field of SEM micrographs …   Wikipedia

  • Microscopy Listserver — The Microscopy Listserver [1] is a network based discussion forum giving members of the scientific community a centralized Internet address to which questions/comments/answers in the various fields of Microscopy or Microanalysis can be rapidly… …   Wikipedia

  • Photoconductive atomic force microscopy — (pc AFM) is a scientific technique.. Multi layer photovoltaic cells have gained popularity since mid 1980s.[1] At the time, research was primarily focused on single layer photovoltaic (PV) devices between two electrodes, in which PV properties… …   Wikipedia

  • Environmental scanning electron microscope — Wool fibers imaged in an ESEM by the use of two symmetrical plastic scintillating backscattered electron detectors …   Wikipedia

  • Transmission electron microscopy — A TEM image of the polio virus. The polio virus is 30 nm in size.[1] Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.