Self-assembled growth of GaSb type-II nanorods aligned along quasiperiodic multiatomic steps on vicinal (111)B GaAs

Self-assembled GaSb nanorods are formed on a vicinal (111)B substrate by molecular beam epitaxy. An atomic force microscope study shows that GaSb nanorods are elongated and aligned along quasiperiodic GaAs multiatomic steps, where the average period of the GaSb nanorod array is nearly twice as large as that of the underlying GaAs multisteps. On average, GaSb nanorods are about 30 nm in width, 84 nm in length, and 2.5 nm in height. In photoluminescence (PL) measurements, the peaks of the GaSb nanorods and wetting layer are observed at 1.07 and 1.29 eV. The PL peaks shift toward higher energies with increasing excitation power density, suggesting that the band lineup exhibit a type-II staggered alignment. In addition, we investigate the temperature dependence of the integral PL intensity of the GaSb nanorods. (C) 2011 Elsevier B.V. All rights reserved.