Intrinsic defects of ZnS epitaxial layers grown by MOVPE

Photoluminescence (PL) and piezoelectric photothermal (PPT) measurements were carried out at 80 K on two different ZnS epilayers grown by using dietliyldisulphide (Et2S2) and dimethyldisulhide (Mt(2)S(2)) sulphur precursors. The sample made by Mt(2)S(2) showed deep centers acting in both nonradiative and radiative recombination processes, whilst the sample grown using the Et2S2, sulphur precursor showed deep centers involved only in radiative recombination processes, as a possible consequence of the lower growth temperature required by the Et2S2 precursor.