Deep electron traps in hydrogenated amorphous silicon

Deep-level-transient-spectroscopy measurements on both Schottky barrier and $p-i-n$ $a$-Si:H solar cell structures reveal deep electron traps. The unique feature of these traps, whose activation energy varies between 0.5 and 1.5 eV, depending on the sample, is that electron capture is thermally activated. This activation energy is close to the trap energy. These traps are also associated with metastable changes in solar cells.