Electroluminescence Analysis of Silicon Solar Cells
Spatial resolved luminescence is a technique designed to reveal recombination, series resistance and processing imperfections of crystalline silicon solar cells. It is applied to monocrystalline and multicrystalline material as well as to the ready devices. The key phenomenon behind the luminescence characterization is the dependence of radiative recombination of minority carriers on the number of important wafer and cell parameters. While single point luminescence characterization was there for quite long time, true spatial analysis without the need of scanning the surface has become possible only recently with the development of Si CCD cameras. There exist two major types of luminescence analysis. The difference between them is the way minority carriers are introduced into the silicon bulk to recombine and give birth to photons. In photoluminescence (PL) minority carriers are excited by the auxiliary light source, which is usually a laser beam and sometimes array of LEDs. The second type is electroluminescence (EL), where the carriers are injected through the metal grid and forward biased p-n junction. EL is only suitable for finished solar cells, while PL can be used for both cells and bare wafers.
The main goal of this project is to improve EL tool currently installed at Solar Power Lab by implementing advanced data acquisition and apply it to analyze industrial type crystalline silicon solar cells.
The specific research objectives are
- Develop Labview program to control power supply and EL camera.
- Learn and implement EL analysis techniques.
- Apply the developed system to silicon solar cell and figure out key loss mechanisms.
Experience in Labview data acquisition and/or power supply control.
To apply, please, send email to Stas Herasimenka (sherasim at asu.edu). Write a couple of words about yourself and why would you like to do research at Solar Power Lab.