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HL: Fachverband Halbleiterphysik

HL 8: Ultrafast Phenomena I

HL 8.7: Vortrag

Montag, 18. März 2024, 16:45–17:00, EW 015

Dynamic Observation of Projected Potentials in Switching Semiconductor Diodes by Time-Resolved Electron Holography — •Tolga Wagner, Hüseyin Çelik, Simon Gaebel, Dirk Berger, and Michael Lehmann — Technische Universität Berlin, Germany

Off-axis electron holography (EH) in a transmission electron microscope (TEM) provides access to nanometer resolved information about the projected electromagnetic potentials of investigated samples. As existing ways for realizing time-resolved measurements in a TEM (e.g. by stroboscopic illumination) have proven to be disadvantageous for EH, such investigations have so far been limited to static measurements.

Recently, a simple, yet promising approach to realize robust time-resolved measurements of periodic processes with nanosecond time resolution in an electron holographic setup by means of interference gating (iGate) was presented. It's based on the synchronized destruction of an interference pattern, relative to an investigated process, where interferometric information is only generated in short undisturbed intervals of a period.

In this presentation, the first application of iGate to switching semiconductor nanostructures, driven at a repetition rate of 3 MHz is demonstrated. By having access to individual frames of the projected electric potential in the area of space charge regions during switching, iGate provides a completely new visual insight into the dynamics of the involved charge carriers with nanometer and nanosecond resolution.

Keywords: Time-Resolved Electron Holography; Interference Gating; Ultra-fast Transmission Electron Microscopy; Nanosecond Observation; Dynamic Electric Potential