At room temperature, the stable phase of bulk ZnS is sphalerite (cubic, space group: F \(\overline{4 }\) 3m). However, nanoscale wurtzite ZnS (hexagonal, space group: P63mc) is also stable and has been synthesized in various forms for electronic applications. In this study, we synthesized wurtzite ZnS up to ~ 50 μm with single crystal-like features using the molten salt-shielded synthesis (MS3) method. The MS3 approach controlled growth kinetics using KBr as a salt medium to cap ZnS polar planes, facilitating a two-step growth process: initial 2D mesocrystalline assembly followed by ‘c’-directional growth through oriented attachments. Analysis indicated sulfur vacancies along the ‘c’ direction, causing lattice parameter contraction due to polar plane capping. This was supported by X-ray diffraction, Raman spectroscopy, photoluminescence (PL), and electron spin resonance spectroscopy (ESR). This method may enable new functional applications, particularly in non-linear optics.
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