Anomalous surface potential behavior observed in InN by photoassisted Kelvin probe force microscopy

摘要

Lattice-polarity dependence of InN surface photovoltage has been identified by an anomalous surface potential behavior observed via photoassisted Kelvin probe force microscopy. Upon above bandgap light illumination in the ambient atmosphere, the surface photovoltage of the In-polar InN shows a pronounced decrease, while that of the N-polar one keeps almost constant. Those different behaviors between N-polar and In-polar surfaces are attributed to a polarity-related surface reactivity, which is found not to be influenced by Mg-doping. These findings provide a simple and nondestructive approach to determine the lattice polarity and allow us to suggest that the In-polar InN, especially that with buried p-type conduction, should be chosen for sensing application.