Polarity Determination of InN by Atomic Hydrogen Irradiation

We have succeeded in determining the polarity of InN by atomic hydrogen (H * ) irradiation for the first time. The surface of N- and In-polar InN films was exposed to H * at nominal temperatures between 200 and 500 °C for 30 to 90 min. After H * irradiation, indium (In) droplets appeared on the surface of N-polar InN, whereas they did not appear on In-polar InN. As the sample temperature was raised, the size of the In droplets on N-polar InN became bigger; furthermore the thickness of the remaining InN layers decreased. On the contrary, the thickness of In-polar InN layers remained unchanged. The mechanisms for these polarity-dependent surface behaviors are discussed. We propose H * irradiation as one of the promising methods for the polarity determination of InN.