Measurement of surface contact potential of AlGaN/GaN heterostructure and n-GaN by Kelvin probe force microscopy

摘要

The contact potential images of the AlGaN/GaN heterostructure and n-GaN before and after thermal treatment have been successfully obtained by Kelvin probe force microscopy (KFM). It was found that the removal of the surface potential shielding effect of the adsorbed water-related layer by means of thermal treatment was effective in the observation of low potential regions at around the dislocations. The low potential regions at dislocations indicated that the dislocations of AlGaN/GaN heterostructure and n-GaN were negatively charged. The contact potential variations around the dislocations in AlGaN/GaN heterostructure was much larger than that of n-GaN in both magnitude and diameter.