Electric properties of Cu‐poor and Cu‐rich Cu(In,Ga)S ₂ films after O ₂ ‐annealing

Abstract

We compare the fundamental electric properties of Cu-poor and Cu-rich Cu(In,Ga)S 2 films before and after annealing, respectively. It has been found that the hole density of Cu-poor films increases after annealing in a O 2 +S combined atmosphere, whereas annealing in S only does not produce a significant effect. We conclude that the oxygen is effective for the passivation of donor-type defects in the Cu-poor Cu(In,Ga)S 2 films. In the case of Cu-rich films, the hole density also increases with O 2 +S-annealing. However, annealing in sulphur atmosphere (no oxygen gas) in this case has comparable consequences. These observations suggest fundamental differences in the incorporation mechanisms of oxygen and sulphur in both types of the film. A tentative model is presented, taking into account results from microstructural characterization of the films.

Segregation of Cu-In-S Elements in the Spray-Pyrolysis-Deposited Layer of CIS Solar Cells

“…Therefore, the next step in improving the conversion efficiency is to control the amount of copper in the Cu-In-S layer. Since the significance of the contribution of a Cu-poor CuInS 2 and CuInSe 2 solar cells has been discussed in the publications [10,11], we believe that a Cu-poor CuInS 2 layer, and hence the presence of Cu 3 In 5 S 9 , may contribute to the photovoltaic effects.…”

Cu(In,Ga)S2 films prepared by two‐stage evaporation on ZnO coated substrates

“…We have previously studied the deposition of Cu-rich Cu(In,Ga)S 2 films for thin film solar cells by two stage multi-source evaporation [6][7][8]. An inherent grading of the Ga/(In+Ga) ratio could be almost avoided by including a certain amount of Cu in the precursor [9,10].…”