Formation of columnar (In,Ga)As quantum dots on GaAs(100)

Columnar (In,Ga)As quantum dots (QDs) with homogeneous composition and shape in the growth direction are realized by molecular-beam epitaxy on GaAs(100) substrates. The columnar (In,Ga)As QDs are formed on InAs seed QDs by alternating deposition of thin GaAs intermediate layers and monolayers of InAs with extended growth interruptions after each layer. The height of the columnar (In,Ga)As QDs is controlled by varying the number of stacked GaAs/InAs layers. The structural and optical properties are studied by cross-sectional scanning tunneling microscopy, atomic force microscopy, and photoluminescence spectroscopy. With increase of the aspect ratio of the columnar QDs, the emission wavelength is redshifted and the linewidth is reduced.

[1]  Mitsuru Sugawara,et al.  Polarization-Independent Photoluminescence from Columnar InAs/GaAs Self-Assembled Quantum Dots , 2002 .

[2]  A. Larsson,et al.  Large ground-to-first-excited-state transition energy separation for InAs quantum dots emitting at 1.3 μm , 2002 .

[3]  T. Jones,et al.  Surface morphology evolution during the overgrowth of large InAs–GaAs quantum dots , 2001 .

[4]  Kohki Mukai,et al.  Molecular beam epitaxial growth of InAs self-assembled quantum dots with light-emission at 1.3 μm , 2000 .

[5]  T. Jones,et al.  Shape and surface morphology changes during the initial stages of encapsulation of InAs/GaAs quantum dots , 2001 .

[6]  Anupam Madhukar,et al.  InAs island‐induced‐strain driven adatom migration during GaAs overlayer growth , 1994 .

[7]  T. E. Lamas,et al.  InAs/GaAs quantum dots optically active at 1.5 μm , 2003 .

[8]  N. Yokoyama,et al.  1.3-μm CW lasing of InGaAs-GaAs quantum dots at room temperature with a threshold current of 8 mA , 1999, IEEE Photonics Technology Letters.

[9]  K. Nishi,et al.  A narrow photoluminescence linewidth of 21 meV at 1.35 μm from strain-reduced InAs quantum dots covered by In0.2Ga0.8As grown on GaAs substrates , 1999 .

[10]  Pm Paul Koenraad,et al.  Determination of the shape and indium distribution of low-growth-rate InAs quantum dots by cross-sectional scanning tunneling microscopy , 2002 .

[11]  R. Nötzel,et al.  Leveling and rebuilding: An approach to improve the uniformity of (In,Ga)As quantum dots , 2002 .

[12]  N. Yokoyama,et al.  Size, density, and shape of InAs quantum dots in closely stacked multilayers grown by the Stranski-Krastanow mode , 2003 .

[13]  M. S. Skolnick,et al.  Structural and optical studies of vertically aligned InAs/GaAs self-assembled quantum dots , 2001 .

[14]  Z. R. Wasilewski,et al.  Coupled InAs/GaAs quantum dots with well-defined electronic shells , 2000 .