Interface analysis of amorphous silicon solar cell structures

Interface properties of amorphous-silicon solar cells have been studied using X-ray photoelectron spectroscopy. The cells used have microcrystalline p- and n-type emitters, and the transparent conductive oxide is commercial SnO2. Compositional information relative to depth has been obtained applying the technique in combination with sputtering for a variable amount of time. I–V characteristics and spectral responses have been interpreted on the basis of the results of the chemical analysis. Certain efficiency-limiting mechanisms have been identified, such as SnO2 chemical reduction by plasma-enhanced chemical vapour deposition (PE-CVD) and aluminium diffusion into the amorphous silicon.