Correlation between transport properties of a-Si:H layers and cell performances incorporating these layers

Using the new ‘quality parameter’, μ0τ0, the authors were able to show, for the first time, a clear correlation between transport properties of a series of a-Si:H films (grown at various deposition temperatures) and the efficiency of p-i-n cells incorporating the same material as i-layer. In this paper, additional experimental data are presented sustaining, on one hand, the validity of the proposed ‘quality parameter’, μoτo, and on the other hand, the existence of a correlation between cell performances and transport properties. Furthermore, limitations of this correlation, due to technological problems (e.g., chemical contamination by Na, O,…) involved in the practical fabrication of a-Si:H solar cells are also illustrated and discussed

Electronic transport in hydrogenated microcrystalline silicon: similarities with amorphous silicon

Undoped hydrogenated microcrystalline silicon (μc-Si:H) layers were grown by the very high frequency glow discharge (VHF-GD) technique under various deposition conditions. The electronic transport properties under illumination were investigated by means of steady-state photoconductivity and steady-state photocarrier grating methods. Similarly to hydrogenated amorphous silicon (a-Si:H), power law dependencies as a function of the generation rate are observed for the photoconductivity, for the ambipolar diffusion length, and for the parameter b (indicating the Fermi level). For μc-Si:H, as for a-Si:H, nearly constant product of (mobility × recombination time) of majority and minority carriers is observed as a function of the parameter b. Based on these similarities, we assume that the electronic transport model developed for a-Si:H remains valid for μc-Si:H