Atmospheric‐Pressure Chemical Vapor Deposition of Iron Pyrite Thin Films

Abstract

Iron pyrite (cubic FeS 2 ) is a promising candidate absorber material for earth-abundant thin-fi lm solar cells. In this report, single-phase, large-grain, and uniform polycrystalline pyrite thin fi lms are fabricated on glass and molybdenum-coated glass substrates by atmospheric-pressure chemical vapor deposition (AP-CVD) using the reaction of iron(III) acetylacetonate and tert -butyl disulfi de in argon at 300 ° C, followed by sulfur annealing at 500-550 ° C to convert marcasite impurities to pyrite. The pyrite-marcasite phase composition depends strongly on the concentration of sodium in the growth substrate and the sulfur partial pressure during annealing. Phase and elemental composition of the fi lms are characterized by X-ray diffraction, Raman spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, Rutherford backscattering spectrometry, and X-ray photoelectron spectroscopy. The in-plane electrical properties are surprisingly insensitive to phase and elemental impurities, with all fi lms showing p -type, thermally activated transport with a small activation energy ( ≈ 30 meV), a roomtemperature resistivity of ≈ 1 Ω cm, and low mobility. These ubiquitous electrical properties may result from robust surface effects. These CVD pyrite thin fi lms are well suited to fundamental electrical studies and the fabrication of pyrite photovoltaic device stacks.

Scientific and Technological Assessment of Iron Pyrite for Use in Solar Devices

“…An optical band gap of % 1.04 eV was found using optical absorption measurements,w hich is close to the reported values in the literature. [7] However, the films were found to be photo-inactive. Electrical measurements revealed the films to be too conducting to be used as ap hoton absorber.…”

“…[7][8][9][10][11] Despitep ossessing such desirable properties,t he success in preparing aw orking solar cell from iron pyrite has been hampered by alack of control on the chemistry of the material and by crystald efects that are believed to be responsible for the low photovoltage output from pyrite solar cells.T he crystal defects manifest as specific material conditions that include Fe-S phase impurities (troilite, greigite,p yrrhotite,e tc. ), stoichiometric deviations, [12][13][14] intrinsic bulk and surface defects, [15][16][17][18] reduced surface energy band gaps, [19] Fermi-level pinning, [20] surface-state-induced band bendinga nd ionized deep donors, [9] and surface inversion layers.…”

“…Several vapor-phase and solution-processing techniques to synthesize iron pyrite were reported, which include sulfurization of iron and iron-oxide thin films, [10,34,[41][42][43][44] electrodeposition, [45] chemical vapor deposition, [7,[46][47][48] spray pyrolysis, [49,50] sputtering, [51,52] hydrothermal method, [53] and hot-injection method. [27,29,54,55] Theq uality of the pyrite thin film is mostly governed by the sulfurization process in almosta ll cases whereas organic ligands used in many chemical synthesis methods play an importantr ole in controlling the size of nanosized pyrite particles.…”

Revisiting Metal Sulfide Semiconductors: A Solution‐Based General Protocol for Thin Film Formation, Hall Effect Measurement, and Application Prospects

“…Although various available techniques such as chemical vapor deposition, [ 9,10 ] atomic layer deposition, [ 11,12 ] molecular beam epitaxy, [ 13,14 ] electrodeposition, [ 7,15 ] successive ionic layer adsorption and reaction, [ 16,17 ] vapor sublimation, [ 18 ] etc., are able to produce thin fi lms of MS, they lack generality or need sophisticated instrumentation, and are complicated. In this context, chemical bath deposition is inarguably the simplest method for thin fi lm deposition.…”

Электрические свойства и энергетические параметры гетеропереходов n-FeS-=SUB=-2-=/SUB=-/p-Cd-=SUB=-1-x-=/SUB=-Zn-=SUB=-x-=/SUB=-Te

“…С использованием пленок p-FeS 2 изготавливают выпрямляющие ток гетероструктуры ZnO/p-FeS 2 [6] и создают омические контакты к p-CdTe в структурах n-CdS/p-CdTe/p-FeS 2 /Au [7]. При участии хлора в процес-сах выращивания пленок, который компенсирует дыроч-ный тип проводимости, получают n-FeS 2 [8]. Используя n-FeS 2 , изготавливают диоды Шоттки n-FeS 2 /M (M = Pt, Au, Nb) [9] и p−i−n-диоды ZnO/FeS 2 /CuI [10].…”