Tailoring the Electronic Properties of GaxIn1-xP Beyond Simply Varying Alloy Composition

Spontaneous ordering in Ga_xIn_1-xP provides the possibility of tuning electronic structure and improving transport properties. A quasiperiodic twinning structure of two ordered variants offers additional flexibilities in designing the material properties. The superstructure is shown to have distinctively different electronic and electrical properties from the single-variant ordered structure, as revealed in polarized elecroreflectance and cross-sectional scanning Kelvin probe force microscopy measurements. The entire potentially accessible range of the "direct" bandgap is defined for this alloy system, and thus the optimal bandgap for any intended application can be achieved through the interplay of the effects of alloying, ordering, and domain structure engineering.