Nanostructured N-polar GaN surfaces and their wetting behaviors

•The wetting behaviors of N-polar GaN were studied for the first time.•A hydrophobic and highly adhesive N-polar GaN was obtaind.•The static friction of the modified N-polar GaN was estimated to be ∼15 mJ/m2.

We report here the wetting behaviors of nanostructured N-polar GaN wafers. The nanostructured GaN samples were obtained by wet photochemical etching under UV illumination. It is confirmed that the wetting behavior of the nanostructured N-polar GaN surfaces follows the Wenzel model. Both surface roughening and decoration with Au nanoparticles will reduce the contact angle (CA), while modification with lauric acid will increase hydrophobility with CAs that change from 42.1° to 129.5°. Besides, the nanostructured surface shows high contact angle hysteresis due to strong static friction that can reach ∼15 mJ/m2.

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