Effect of the metal-semiconductor interface on carrier collection in a-Si: H Schottky barrier solar cell structures

Abstract

Abstract The internal quantum efficiencies of intrinsic hydrogenated amorphous silicon (a-Si:H) Schottky barrier solar cell structures have been used to determine the effects of the metal/a-Si:H contact on the collection of photogenerated carriers. The results of different metal contacts, as well as controlled interfacial oxides, are analyzed using a detailed numerical model AMPS (analysis of microelectronic and photonic structures). Direct correlation is established between the nature of the interface and the short wavelength quantum efficiencies where electron back-diffusion to the metal contact is the primary loss mechanism of carriers photogenerated at these lower wavelengths. The results are also found to be consistent with electron surface recombination velocities at the metal/a-Si:H contact which depend not only on the metal work function and the presence of an interfacial oxide but also on the formation of metal silicides.