Effect of Substrate Faceting on Epitaxial Lead Sulfide Thin Films Deposited from a Solution onto GaAs(100)

Lead sulfide (PbS) thin films were deposited from a solution onto chemically etched GaAs substrates. The substrates were etched using two different chemical etchants, citric acid and phosphorous acid, resulting in different substrate roughness values from 0.4 nm up to 6.2 nm. In both cases, etching resulted in the simultaneous exposure of (100), (111), and (311) microfacets. These different substrate conditions had a strong impact on the morphology and microstructure of the PbS films. This work provides the first reported evidence for PbS thin films deposited onto GaAs(311) microfacets with {113}/⟨110⟩ twinning relations.