Presentation: 2025 ND EPSCoR Annual conference 

October 21, 2025, NDSU Memorial Union, Fargo, North Dakota

Structural and electronic properties of CdSe crystal surfaces

Cadmium Selenide (CdSe), a II–VI semiconductor, has attracted broad interest for its potential in chemical and biochemical sensing, as well as photocatalytic reactions. In both applications, the activity and efficiency of these materials strongly depend on the properties of its exposed crystal facets, which control charge separation, carrier transport, catalytic reactivity, and the interaction with molecular adducts and environment. A detailed atomistic understanding of these properties is therefore essential for designing CdSe-based materials that combine sensitivity with stability. We computationally investigated the structural and electronic properties of the CdSe surfaces, focusing on two main questions. First, we compared the electronic properties of the two main polymorphs, Wurtzite and Zinc Blende, to clarify how surface structure influences electronic and optical responses, and thereby affects their photo-reactivity. Secondly, the influence of quantum confinement was explored by systematically varying the slab model thickness, ranging from a single monolayer to eight monolayers. Our study focuses particularly on the work function, a property that governs electron transfer at surfaces and is directly linked to sensing efficiency and photocatalytic activity. We have found that non-polar, stoichiometric surfaces indicate a diminishing effect of slab thickness on the work function, saturating at approximately ten monolayers. For polar surfaces, significant surface reconstruction effects were observed, particularly for structures of a few layers thick. Importantly, the calculated values of work functions fall within the experimental range, validating the modeling approach and strengthening the link between atomic-level structure and functional performance.