Indium segregation during multilayer InAs/GaAs(001) quantum dot formation

Indium segregation during the growth of multilayer InAs/GaAs(001) quantum dot (QD) structures has been studied using reflection high-energy electron diffraction (RHEED) measurements of the critical coverage (θ crit ) for second layer QD formation. A model bilayer structure was used in order to separate the effects of segregation and strain. The structure comprises an upper QD layer formed on top of a buried two-dimensional InAs layer. Growth temperature and the GaAs spacer layer thickness (S) are both found to have a significant effect on θ crit . Indium segregation during growth of the capping layer leads to the presence of a surface In adatom population prior to deposition of the second InAs layer. Segregation occurs for S up to 8 nm at 510°C, this value being reduced by ∼50% at 450 °C. (C) 2005 Elsevier B.V. All rights reserved.

[1]  B. Abbey,et al.  Strain-interactions between InAs/GaAs quantum dot layers , 2004 .

[2]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[3]  Moison,et al.  Surface segregation of third-column atoms in group III-V arsenide compounds: Ternary alloys and heterostructures. , 1989, Physical review. B, Condensed matter.

[4]  Andrew G. Glen,et al.  APPL , 2001 .

[5]  Dennis G. Deppe,et al.  1.3 μm InAs quantum dot laser with To=161 K from 0 to 80 °C , 2002 .

[6]  Ray Murray,et al.  Optical properties of bilayer InAs/GaAs quantum dot structures: Influence of strain and surface morphology , 2002 .

[7]  C. Heyn.  Critical coverage for strain-induced formation of InAs quantum dots , 2001 .

[8]  B. A. Joyce,et al.  Composition of InAs quantum dots on GaAs(001): Direct evidence for (In,Ga)As alloying , 1998 .

[9]  T. Jones,et al.  Strain-engineered InAs'GaAs quantum dots for long-wavelength emission , 2003 .

[10]  Edmund Clarke,et al.  Competition between strain-induced and temperature-controlled nucleation of InAs/GaAs quantum dots , 2004 .

[11]  O. Schmidt,et al.  Closely stacked InAs/GaAs quantum dots grown at low growth rate , 2002 .

[12]  H. Toyoshima,et al.  In surface segregation and growth-mode transition during InGaAs growth by molecular-beam epitaxy , 1993 .

[13]  B. A. Joyce,et al.  Surface alloying at InAsGaAs interfaces grown on (001) surfaces by molecular beam epitaxy , 1997 .

[14]  T. Jones,et al.  Variations in critical coverage for InAs/GaAs quantum dot formation in bilayer structures , 2002 .

[15]  Kobayashi,et al.  Vertically self-organized InAs quantum box islands on GaAs(100). , 1995, Physical review letters.