Phase controlled low-pressure chemical vapor deposition of iron(di)sulfide

Thin films of iron(di)sulfide pyrite, marcasite, and pyrrhotite have been prepared on glass substrates by low-pressure chemical vapor deposition (LPCVD) from iron(III)acetylacetonate (Fe(acac)3) and tert-butyl disulfide (TBDS), using a cold-wall LPCVD reactor. It is found that the temperature determines the crystalline phases of the films. Deposition temperatures of 350 and 375°C yield pure polycrystalline pyrite with an indirect and a direct band gap of 0.95 and 1.45 eV, respectively. By increasing the temperature up to 425°C, a mixture of pyrite, marcasite, and pyrrothite is formed, while between 425 and 450 °C mixtures of pyrite and pyrrhotite are obtained. Temperatures of 480 °C cause the formation of pyrrothite films