(Color online) Layer sequence for the Sb QW structures.
(Color online) RHEED patterns along the ⟨110⟩ and ⟨211⟩ directions for a GaSb (111)A surface under an Sb flux at (a) ∼580 °C after growth of the GaSb buffer layer, (b) ∼470 °C with negligible Sb on the surface, (c) ∼330 °C with some Sb at the surface, and (d) ∼220 °C with complete Sb coverage of the surface.
(Color online) RHEED patterns along the ⟨110⟩ and ⟨211⟩ directions for a GaSb (111)A surface (a) at ∼600 °C, after the growth of a GaSb buffer layer under an Sb flux, and a GaSb (111)A surface at ∼ 280 °C without a Sb flux, (b) just before the Sb QW growth, (c) after the Sb QW growth, and (d) after the GaSb cap layer growth. The RHEED patterns in (d) were captured during a different growth than the patterns in (a)–(c).
(Color online) Cross-sectional SEM images of thick Sb films grown at 300 °C for deposition times of (a) 60 min and (b) 30 min. The images show thicknesses (∼360 and ∼174 nm) that scale well with deposition times. Roughness due to cleaving can be seen in the images.
(Color online) Cross-sectional TEM images of an ultrathin Sb structure showing (a) a larger area of the well-ordered ultrathin Sb layer, and (b) sharp interfaces between the Sb and GaSb layers under high resolution. The images were captured from the ⟨211⟩ direction. A nonuniform coverage of the GaSb cap layer is seen in both images. In (a), the image contrast due to a threading dislocation (TD) can be seen.
Plan view FE-SEM images of the surface of an ultrathin Sb structure (a) grown at 300 °C with a ∼3 nm GaSb cap layer, (b) grown at 280 °C with a ∼6 nm GaSb cap layer, and (c) grown at 280 °C without a GaSb cap layer. The thickness of the Sb layer is noted in each image. The surface morphology of both the cap layer and the Sb layer grown at 280 °C is more uniform than for the capped structure grown at 300 °C. The scale bar is 1 μm long.
(Color online) Two-dimensional electrical resistivity vs temperature for capped ultrathin Sb layers with different thicknesses grown at 280 °C.
Article metrics loading...
Full text loading...