Synthesis of Pyrite (FeS2) Thin Films by Low-Pressure MOCVD

Abstract

Thin films of iron disulfide have been prepared by low-pressure CVD (LPCVD) from iron(III) acetylacetonate (Fe(acac) 3 ), tert-butyldisulfide (TBDS), and hydrogen. The influence of the relevant CVD parameters on the growth rate, chemical composition (stoichiometry), morphology, crystalline phases, and contaminants has been examined. Pyrite thin films with a uniformity variation of less than 5 % over a length of 10 cm are obtained in a hot-wall LPCVD reactor. The present study shows that these films are deposited without detectable iron sulfide (FeS) phases at temperatures from 300 C up to 340 C on glass and silicon substrates. Growth rates vary between 0.2 nm min ±1 and 12 nm min ±1 . In all cases, the films are polycrystalline pyrite with an indirect bandgap of 0.95 ± 0.05 eV, and a dark specific resistance of 0.5±1.0 W cm. The absorption coefficient of the films is 3 ± 1´10 5 cm ±1 at l = 500 nm.

First-principles studies of the electronic properties of native and substitutional anionic defects in bulk iron pyrite

“…61,62 In their view, pyrite is probably a line compound with a sulfur-to-iron ratio of 2.00 (i.e., a phase width of less than one percent). A number of papers have found substantial nonstoichiometry in polycrystalline pyrite thin films using Rutherford backscattering spectrometry (which has a best-case accuracy of ~1 at.%), energy dispersive spectroscopy, and similar techniques 61,63,64,65,66 However, the presence of sulfur-deficient phase impurities (in cases of S:Fe < 2.00) or excess sulfur at surfaces and grain boundaries (in cases of S:Fe > 2.00) may explain most if not all of these results. Evidence for sulfur divacancies and vacancy clusters in pyrite by positron annihilation spectroscopy has also been reported, 16 but these studies are in our view preliminary and far from conclusive.…”

Iron Disulfide (FeS2): A Promising Material for Removal of Industrial Pollutants

“…Various methods to synthesize FeS 2 nanostructures have been reported including thermal sulphidation/sulfarization process, [12][13] chemical vapour deposition, [14][15] hot injection method [16] and hydrothermal method, [17][18] plasma spray process [19] and solvothermal method. [20] Among these methods, hydrothermal method was preferred due to its low temperature process which helps to reduce impurities and surface defects.…”

Deposition of iron sulfide thin films by AACVD from single source precursors

“…Different phases of iron sulfide nanoparticles were produced by high-energy mechanical milling combined with mechanochemical processing for FeS and FeS 2 [27], dendrimer-stabilized FeS [28], solvothermal synthesis of Fe 3 S 4 [29], sulfur-reducing bacteria for Fe 1 À x S and Fe 3 S 4 [30,31], laser pyrolysis of iron complexes for FeS [32], polymer-stabilized wet chemical synthesis of FeS [33], reverse micelles for FeS 2 [34], and the decomposition of single-source precursors for FeS 2 [35]. Meester et al [36] prepared iron disulfide (FeS 2 ) using iron(III) acetylacetonate [Fe(acac) 3 ], tert-butyl disulfide, and hydrogen. There have been a very limited number of iron complexes employed as single-source precursors for the deposition of iron sulfide as Fe 1 þ x S, FeS 2 , and Fe 1 À x S thin films, which include dithiocarbamato complexes [Fe(S 2 CNRR 0 ) 3 ] (R, R 0 ¼Et, Et, 1 Me, i Pr) [37] and the sulfur-bridged binuclear iron carbonyl complex [Fe 2 (CO) 6 (m-S 2 )] [38].…”