Nonradiative and radiative recombination processes of zns epitaxial layers

Room temperature photoluminescence (PL) and piezoelectric photothermal (PPT) spectroscopy were successfully performed on two different ZnS epitaxial layers grown by pyrolytic MOVPE on GaAs(100) by using diethyldisulphide (Et2S2) as sulphur precursor at 390 °C and 435 °C. PL spectra allowed to identify several radiative recombination channels [namely, self-activated (SA) bands] associated to deep centres. Intense SA band occurred in PL and in PPT spectra recorded from ZnS grown at low temperature, indicating that RT radiative and non-radiative transitions both increases with decreasing the growth temperature below 400 °C.