Amorphous Silicon for Solar Cell Applications: Defect Generation, Annealing, and Equilibrium.

The underlying physical principles of defects in amorphous silicon and its alloys are discussed in the context of their primary application, in thin film photovoltaic devices. The economic and performance goals for solar cells are reviewed, and an introduction to amorphous semiconductor device principles is presented. Various optical and electronic techniques for defect identification are developed and discussed, with special emphasis on a comparison of results from many techniques measured on the same material. The processes by which defects are produced, removed, and the thermal equilibrium between production and annihilation of defects are elucidated. The consequences of these defect processes for solar cell performance and stability are calculated and compared with experiment.