Characterization of Nitrogen-Doped ZnSe and ZnS_0.06Se_0.94 Films Grown by Metal-Organic Vapor-Phase Epitaxy

Abstract

The relations of doped nitrogen (N) and deep-level emissions such as Y lines (477 nm) and self-activated (SA) emissions (∼580 nm) were investigated in detail by photoluminescence measurements mainly in ZnS 0.06 Se 0.94 films lattice-matched to GaAs. The Y and SA emissions in the N-doped ZnS 0.06 Se 0.94 films both showed appearance of a `threshold' for the incident optical power, indicating the existence of the activation energy on these lines. Persistent photoconductivity was observed for the first time in the N-doped ZnS 0.06 Se 0.94 films which corresponds with the above new finding. The electrical property of the lattice-matched ZnS 0.06 Se 0.94 film was p -type with a carrier concentration of 7×10 15 cm -3 which is the highest carrier concentration ever reported with N-doping, while the lattice-mismatched ZnSe film was highly resistive. It was pointed out that the partial incorporation of the doped N-into the defect sites related to the Y line is still compensating the p -type property, even in the lattice-matched films.