Nucleated Growth of Iron Pyrite on Highly Oriented Pyrolytic Graphite (HOPG) by Chemical Vapor Deposition (CVD)

Iron pyrite, one of the phases in the FeS2 system, is a promising semiconductor for use in solar cell applications due to its earth-abundance, high absorption coefficient, and suitable bandgap. However, currently the efficiency of iron pyrite solar cell device does not exceed 3% [1]. Many studies attempted to understand the cause of the low open-circuit voltage in pyrite devices. Some studies suggested that this is due to the naturally occurring metallic FeS-like phase impurities such as marcasite, pyrohotite, or troilite [2]. Other studies have demonstrated that sulfur and iron vacancies at the surface can cause the low open-circuit voltage [3]. Despite many efforts have been made to improve the efficiency of pyrite, it is incompletely understood how to preferentially grow solely pyrite. Thus, it is essential to understand the basic fundamental mechanisms of pyrite growth. As one of the methods, we examined the growth of pyrite particles in the presence of nucleation sites.