This technique is useful to identify defect/trap levels in the bandgap. In this technique, the sample is excited with a chopped light. The differantial photocurrent, sampled between t 1 and t 2 decay times, is recorded using a lock-in amplifier connected to the multivibrator/gate/sample and a hold circuit. Using the photocurrent decay curves of the PITS signal at some determined t 1 and t 2 decay times, activation energies and capture cross-sections of the defects/traps can be calculated.
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