Optimization of electronic-band alignments at ferroelectric (ZnxCd1−x)S/Si(100) interfaces

We have obtained ferroelectric characteristics from nonoxide (ZnxCd1−x)S (x=0.1–0.3) thin films. On the basis of x-ray photoelectron and visible–ultraviolet light absorption spectroscopy measurements, the conduction-band discontinuity at the (ZnxCd1−x)S/Si(100) interfaces is found to vary between 0.4 and 1.3 eV with a change in composition x between 0.1 and 0.9. The leakage current density, which strongly depends on the conduction-band discontinuity, is reduced to less than 10−6 A/cm2 at a gate voltage of 4 V.