Transient measurements with an ultrafast scanning tunneling microscope

Ulrich Dieter Felix Keil, Jacob Riis Jensen, Jørn Märcher Hvam

    Research output: Contribution to journalJournal articleResearchpeer-review


    We use a photoconductively gated ultrafast scanning tunneling microscope to resolve laser-induced transients on transmission lines and photoconductors. The photoconductive switch on the tunneling probe is illuminated through a rigidly attached fiber. The use of the fiber enables us to scan across the transmission line while the change in delay time between pump beam (on the sample) and probe beam (on the probe) provides the temporal information.

    The investigated photoconductor sample is a low-temperature-grown GaAs layer placed on a sapphire substrate with a thin, semitransparent gold layer. In tunneling mode the probe is sensitive to laser-induced field changes in the semiconductor layer. Laser-induced transient signals of 2.2 ps widths are detected. As for the transmission lines, the signals can be explained by a capacitive coupling across the tunneling gap.
    Original languageEnglish
    JournalApplied Physics A: Materials Science & Processing
    Issue numberS
    Pages (from-to)S23-S26
    Publication statusPublished - 1998


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