Atomic Layer Deposition and Pulsed Chemical Vapor Deposition of SnI2 and CsSnI3

High Resolution Image Download MS PowerPoint Slide Halide perovskites, such as CsSnI 3, are materials renowned for their exceptional optoelectronic properties. CsSnI 3 stands out as a desirable choice for nontoxic and environmentally friendly absorber layers in perovskite solar cells (PSC) due to the absence of lead in its composition. However, the limited ability to deposit conformal and scalable halide perovskite thin films remains a significant obstacle to the wide commercialization of PSCs. In this study, we use atomic layer deposition (ALD) to tackle this obstacle. We present two new ALD processes: SnI 2 and CsSnI 3 . The SnI 2 process operates at low temperatures within a narrow range (75–100 °C) and has a growth per cycle (GPC) of 0.9 Å. By depositing ALD CsI and subsequently ALD SnI 2 at different temperatures, we successfully obtain phase-pure γ-CsSnI 3 films via a conversion reaction. Moreover, we demonstrate an alternative method for γ-CsSnI 3 film deposition by replacing the ALD SnI 2 with a pulsed chemical vapor deposition (pulsed CVD) SnI 2 step. This pulsed CVD SnI 2 step operates at temperatures compatible with the ALD CsI process, effectively making it a one-step process (effective GPC > 2.0 Å) compared to the ALD conversion while retaining its conformality characteristics.