Atomic ordering of GaInP studied by Kelvin probe force microscopy

The atomic ordering of GaInP has been established and studied by a variety of methods, including transmission electron microscopy, cathodoluminescence, and photoluminescence. In this work, a Kelvin probe force microscope (KPFM) has been employed to image several GaInP samples previously characterized by these established techniques. The results of our study clearly show that the KPFM is capable of distinguishing between ordered and disordered regions in GaInP, and that the KPFM contrast strongly depends on the amplitude of the applied ac bias voltage of the KPFM. The measurements indicate that ordering in GaInP modifies the density and/or lifetime of the surface states.