DISORDER OF ZNSE/ZNS STRAINED-LAYER SUPERLATTICES BY N+ OR LI+ ION-IMPLANTATION AND LOW-TEMPERATURE ANNEALING

We demonstrate layer disordering of ZnSe/ZnS strained-layer superlattices (SLSs) induced by low-damage N+ or Li+ ion implantation and low-temperature annealing. The interdiffusion of Se and S atoms was observed by secondary-ion mass spectrometry analyses. By reflectance measurements, a significant decrease in the refractive index, which is useful for waveguiding applications, was measured in the disordered SLS. In photoluminescence (PL) spectra, strong excitonic emission around 400 nm was observed in the disordered SLS corresponding to a damage recovery. A slight red shift of the PL peak observed in the early stages of annealing is interpreted as the relaxation of misfit strain by interdiffusion. For longer annealing times, the PL peak for an implanted SLS shifted towards the higher energy side, which clearly indicates layer disordering of the SLSs. This low-temperature planar process will be very useful for the fabrication of II-VI semiconductor optoelectronic devices.