Electronic recombination losses at the wafer surface significantly reduce the efficiency of Si solar cells. Surface passivation using a suitable thin dielectric layer can minimize the recombination losses. Herein, advanced passivation using simple materials (Al2O3, HfO2) and their compounds H(Hf)A(Al)O deposited by atomic layer deposition (ALD) was investigated. The chemical composition of Hf and Al oxide films were determined by X-ray photoelectron spectroscopy (XPS). The XPS depth profiles exhibit continuous uniform dense layers. The ALD-Al2O3 film has been found to provide negative fixed charge (−6.4 × 1011 cm−2), whereas HfO2 film provides positive fixed charge (3.2 × 1012 cm−2). The effective lifetimes can be improved after oxygen gas annealing for 1 min. I-V characteristics of Si solar cells with high-κ dielectric materials as passivation layers indicate that the performance is significantly improved, and ALD-HfO2 film would provide better passivation properties than that of the ALD-Al2O3 film in this research work.

Fundamental obstacles such as low production yields, non‐reproducibility, and non‐uniformity over large area are encountered in the commercialization of copper indium gallium (di) selenide (CIGS) solar cell. The precise control and manipulation of the thin film's local chemical compositional distribution during production is particularly difficult. In this paper, we develop a concept of metal organic (MO) sputtering using metal organic precursor in which the film compositions could be fine‐tuned and tailored according to programmed intelligent material and device design. An essential feedback control of the film compositions using optical spectroscopy is crucial. Moreover, the addition of sulfur to enlarge the band gap of CIGS film is indispensable to improve the cell efficiency. We are also developing the chemical sulfurization technique, in which the sulfur and selenium atoms are interchanged in solution at room temperature and large band gap copper indium gallium sulfur‐selenide (CIGSS) films can be obtained. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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