lock-in -ELYMAT

A master thesis 'Einsatzmöglichkeiten von Lock-in-Technik in Verbindung mit dem ELYMAT-Meßprinzip' written by Sönke Köster, was performed in our working group during 8/1994 and 7/1995.

By chopping the laserlight it is possible to get a better signal to noise ratio when using the lock-in technique for ELYMAT measurements. The measured signal is the front or back side photo current, which is modulated by the alternating laser generation. A two phase lock-in amplifier is recomended, because phase and amplitude is influenced by the bulk minority carrier lifetime.

In FPC mode frequencies up to 50 kHz are possible, while in BPC even with frequnces of a few kHz large phase and amplitude reduction occurs.

For question send an e-mail to:

• jc@tf.uni-kiel.de
• wl@tf.uni-kiel.d400.de