Suns-Voc System: Measure Illumination-Voc curves any time after Phosphorus diffusion!
The great part about the Suns Voc system is that it gives the solar cell current voltage curve without the effects of series resistance. The measurement is extremely fast, taking only a few seconds so that the limiting speed is the time to place the wafer on the test block. Since the Suns Voc uses a flash test, the temperature is stable throughout the measurement.
The SunsVoc system is now available as a standalone unit complete with a temperature controlled block.
The data can either be analyzed as a Suns-Voc curve (above)
or or in the form of the Standard Photovoltaic curve (below). This standard
IV curve can be used to characterize shunting. It is measured at Voc,
so it has no series resistance.
Comparing this curve to the final IV curve gives a precise measure of
the series resistance.
The Suns-Voc stage is ideal for measuring wafers after Al
firing, and then again after
front-grid firing. This allows optimization and monitoring of these steps
to maintain voltage,