Abstract
InAs/GaAs quantum dots (QDs) were grown by low pressure Metal Organic Chemical Vapor Deposition in Stranski-Krastanov growth mode. The influence of growth temperature on the QD density was investigated. Atomic Force Microscopy (AFM) was used to study the growth behaviour of the QD structure. It was identified that the growth temperature plays major role in determining the growth and distribution of InAs QDs due to the temperature-dependent dislocation propagation from the GaAs substrate. A high InAs on GaAs QD density 6.4 x 1010 cm-2 was obtained and this proposes a potential superiority of nanodevice operation.
Highlights
Low dimensional semiconductor structures have reached great interest due to their modified electronic and optical properties
Growth by Metal Organic Chemical Vapor Deposition (MOCVD) has proved more challenging with relatively few reports of MOCVD grown InAs/GaAs quantum dots (QDs) [5,6,7,8]. This is due to an increase role of growth kinetics which can lead to island coalescence and defect formation
We will discuss the influence of the growth temperature ranging from 500 to 600 oC for the InAs/GaAs system fabricated on n-type GaAs wafer
Summary
Low dimensional semiconductor structures have reached great interest due to their modified electronic and optical properties. Quantum dot structures, which provide electron confinement in three dimensions, can be grown in-situ, without using lithography, by the so-called “self-assembly” effect or Stranski-Krastanov (S-K) growth mode In this growth mode at a certain critical thickness, an initially two-dimensional (2D) epitaxial layer under compressive strain relaxes into self organized three-dimensional (3D) coherent islands (dots), and a remaining thinner 2D wetting layer [1]. Growth by Metal Organic Chemical Vapor Deposition (MOCVD) has proved more challenging with relatively few reports of MOCVD grown InAs/GaAs QD [5,6,7,8] This is due to an increase role of growth kinetics which can lead to island coalescence and defect formation. The critical issue is to avoid formation of larger islands which are susceptible to dislocation formation in MOCVD growth, yet still achieve the high QD densities necessary for device applications
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