Tin Lodide Thin Films Growth via Plasma Enhanced Chemical Vapor Deposition and its Optimization Using V–I Probe Impedance Analyser for Optoelectronic Applications

Abstract

Tin(ii) iodide (SnI2) faces significant challenges in photodetector applications, primarily due to its sensitivity to moisture and degradation over time. Achieving uniform, high‐quality films with low impurity and defect levels is also a challenge. Potential solutions include advanced deposition techniques to improve film quality and stability, surface passivation and encapsulation, doping and alloying. In this study, SnI2 thin films have been deposited for the first time using plasma enhanced chemical vapour deposition (PECVD) technique to the best of our knowledge. Process parameters like deposition pressure and RF‐power have been optimised via non‐intrusive in‐situ V−I probe impedance analyser. SnI2 thin films have been deposited on glass & transparent conducting oxide (TCO) and p‐Si wafer at various RF‐power to make SnI2/p‐Si heterojunction followed by metallization to make Ag/SnI2/p‐Si/Ag heterojunction photodetector. Characterization techniques like thin film thickness measurement, UV‐Vis‐NIR spectroscopy, Photoluminescence spectroscopy, glancing incidence x‐ray diffraction (GIXRD), SEM and I−V measurements were carried out to study its optical, structural and electronic properties. Fabricated devices, Ag/SnI2/p‐Si/Ag heterojunction photodiode exhibits best critical performance for the film deposited at 150 W having rectifying ratio of 6.9×104 at 1.0 V and photo‐sensitivity of 1.6×104 at 100 mW/cm2 light intensity.