Observation of the diffraction of a helium-neon laser beam on the monoatomic steps of a vicinal sapphire surface

Michel Lintz (1) , Marie-Anne Bouchiat (1)

1 LKB (Lhomond) - Laboratoire Kastler Brossel

"Vicinal" surfaces, with equally spaced monoatomic steps, can be obtained by thermally annealing single crystals of materials like sapphire or silicon. We have observed the diffraction of a helium-neon laser beam on the monoatomic steps of a (0 0 0 1) vicinal sapphire wafer surface. Diffraction angles were in the range 40-50degrees, in agreement with the AFM-measured terrace length. Both sides of the wafer gave rise to lowest-order diffracted beams. This method allows one to determine surface characteristics such as the direction, average length and regularity of the terraces on the area illuminated by the laser. In the tested sample the direction of the crystal C axis could be shown to be uniform to within 5" over a 12 min area of the sample.

Mots clés: surface morphology; surface roughness; diffraction by a grating; vicinal surface; single crystal; aluminum oxide; thermal reconstruction; monoatomic steps

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Optique [physics.optics]

Michel Lintz, Marie-Anne Bouchiat. Observation of the diffraction of a helium-neon laser beam on the monoatomic steps of a vicinal sapphire surface. Surface Science : A Journal Devoted to the Physics and Chemistry of Interfaces, 2002, 511, pp.L319-L324. ⟨10.1016/S0039-6028(02)01569-8⟩. ⟨hal-00002726⟩