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Transient Lifetime Mapping Tool in the Integrated Measurements and Characterization Cluster Tool

This page provides details on transient lifetime mapping in the Integrated Measurements and Characterization cluster tool. This capability is planned to be operational in 2009.

Photo of a blue-framed rack that holds a metal horizontal cylindrical chamber with three viewing ports and several flanges visible.  Other components are mounted above and along side this chamber. To the right is a blue table with a large laser on top. This unit is all within a black-curtained enclosure.

Photoluminescence tool, which is part of the the Integrated Measurements and Characterization cluster tool, showing the laser in set-up mode within the optical enclosure.

The transient lifetime mapping tool contains systems for measuring minority-carrier lifetime in a vacuum chamber for integrated processing and measurements. It features a tunable, Q-switched laser as the excitation source and uses the following techniques for lifetime measurement:

  • Microwave reflection photoconductive decay (μPCD)
  • Resonant-coupled photoconductive decay (RCPCD). NREL has three patents on this technique.


  • Measuring lifetimes by transient decay using various injection levels and wavelengths of light for excitation.

Special features:

  • Excitation light from laser is tunable from ~420 to ~2400 nm, and it pulses 30 times per second; pulses are ~10 ns wide
  • Measurements are in vacuum
  • Two RCPCD ports—one with a small spot for mapping with ~1-mm resolution, and a second with a larger spot for increased sensitivity measurements averaged over a large area
  • Microwave reflection lifetime system with small spot for mapping.

Contact Steve Johnston for more details on these capabilities.