González Taboada, Alfonso and Sanchez, A.M. and Beltran, A.M. and Bozkurt, M. and Alonso Alvarez, Diego and Alén Millán, Benito and Rivera de Mena, Antonio and Ripalda Cobián, Jose María and Llorens, J.M. and Martín-Sánchez, J.A. and González Diez, M. Yolanda and Ulloa Herrero, José María and García Martín, Jorge Miguel and Molina Rubio, Sergio Ignacio and Koenraad, P.M.
Structural and optical changes induced by incorporation of antimony into InAs/GaAs(001) quantum dots.
"Physical Review B", v. 82
We present experimental evidence of Sb incorporation inside InAs/GaAs(001) quantum dots exposed to an antimony flux immediately before capping with GaAs. The Sb composition profile inside the nanostructures as measured by cross-sectional scanning tunneling and electron transmission microscopies show two differentiated regions within the quantum dots, with an Sb rich alloy at the tip of the quantum dots. Atomic force microscopy and transmission electron microscopy micrographs show increased quantum-dot height with Sb flux exposure. The evolution of the reflection high-energy electron-diffraction pattern suggests that the increased height is due to changes in the quantum-dot capping process related to the presence of segregated Sb atoms. These structural and compositional changes result in a shift of the room-temperature photoluminescence emission from 1.26 to 1.36 μm accompanied by an order of magnitude increase in the room-temperature quantum-dot luminescence intensity.