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SnS2 is a two-dimensional (2D) layered semiconductor with a visible-range bandgap (~2.3eV), high charge carrier mobility, long carrier lifetimes, and good environmental stability. This study explores the impact of zero-valent metal intercalation into the van der Waals gaps of SnS2 on charge carrier dynamics. We demonstrate that metal intercalation enhances optical absorption in the yellow-to-IR range and induces metal-dependent bandgap shifts. Time-resolved THz spectroscopy reveals that different metals uniquely influence photoconductivity dynamics: We find that intercalation with Bi, Ni, and Fe shortens the photoconductivity decay times, whereas Rh intercalation results in a slower decay. These findings highlight the potential of metal intercalation to tailor SnS2 properties for diverse applications, from solar energy conversion to high-speed photodetectors. 

Abstract Above‐band gap optical excitation of non‐centrosymmetric semiconductors can lead to the spatial shift of the center of electron charge in a process known as shift current. Shift current is investigated in single‐crystal SnS₂, a layered semiconductor with the band gap of ≈2.3 eV, by THz emission spectroscopy and first principles density functional theory (DFT). It is observed that normal incidence excitation with above gap (400 nm; 3.1 eV) pulses results in THz emission from 2H SnS₂() polytype, where such emission is nominally forbidden by symmetry. It is argued that the underlying symmetry breaking arises due to the presence of stacking faults that are known to be ubiquitous in SnS₂single crystals and construct a possible structural model of a stacking fault with symmetry properties consistent with the experimental observations. In addition to shift current, it is observed THz emission by optical rectification excited by below band gap (800 nm; 1.55 eV) pulses but it requires excitation fluence more than two orders of magnitude higher to produce same signal amplitude. These results suggest that ultrafast shift current in which can be excited with visible light in blue–green portion of the spectrum makes SnS₂a promising source material for THz photonics.