Quasi-Steady-State Lifetime Measurements

Quasi-Steady-State lifetime measurements rely on the number of carriers present when a steady light is shone on a sample. It is assumed that the intensity of the flash changes sufficiently slowly so that carrier populations in the sample are always is steady state. This condition is met so long as the sample lifetime is less than the characteristic decay of the flash lamp.

The generation rate is determined by measuring the amount of light falling of the cell and then correcting for the reflectivity and the absorption coefficient of silicon (ref).

Illumination at Reference Cell and Carrier Density

Minority-Carrier Lifetime (no Auger correction) vs. Carrier Density

QSS lifetime measurement