PHOTOCURRENT SPECTROSCOPY OF EXCITONIC TRANSITIONS IN CDZNS/ZNS STRAINED-LAYER SUPERLATTICES

We report the first observation of excitonic transitions in the photocurrent spectra (PCS) of MQW Cd(x)Zn1-xS/ZnS (x = 0.25) strained-layer superlattices (SLS). In electric field dependent PCS measured at 14 K and at room temperature, we have observed a significant blueshift of the peak energy and photocurrent enhancement with increasing applied field. These results may be fully explained by assuming that this strained superlattice system exhibits a type II band lineup. Preliminary results for photo-detection in the ultraviolet are also presented and these suggest the possibility of producing a photo-modulator in the green to UV region of the spectrum.