  Using first-principles density functional calculations, we have studied the
structural stability of stoichiometric as well as non-stoichiometric CdS
nanoclusters at ambient pressure with diameters ranging up to about 2.5 nm. Our
study reveals that the relative stability of the two available structures for
CdS, namely zinc blende and wurtzite, depends sensitively on the details like
surface geometry and/or surface chemistry. The associated band gap also
exhibits non-monotonic behavior as a function of cluster size. Our findings may
shed light on reports of experimentally observed structures and associated
electronic structures of CdS nanoclusters found in the literature.
