1. Thermodynamic modelling of InAs/InP(0 0 1) growth towards quantum dots formation by metalorganic vapor phase epitaxy.
- Author
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Hasan, Samiul, Merckling, Clement, Pantouvaki, Marianna, Meersschaut, Johan, Van Campenhout, Joris, and Vandervorst, Wilfried
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THERMODYNAMIC molecular model , *QUANTUM dots , *OPTOELECTRONIC devices , *SURFACE energy , *METAL organic chemical vapor deposition - Abstract
Highlights • The epitaxial S-K InAs/InP(0 0 1) growth is impacted by As/P exchange process. • Two transitions have been observed in S-K InAs/InP(0 0 1) growth (three regimes). • Three regimes are: 2D layer, large 3D islands, and quantum dots growth. • The truncated pyramidal large 3D islands transform into spherical cap quantum dots. • All experimental transitions are explained through thermodynamic modeling. Abstract Quantum Dots (QDs) are considered as an efficient building block of many optoelectronic applications, such as semiconductor laser, photodetector, whereby their physical dimension is the key parameter to be controlled. In this work, we have studied experimentally the growth of InAs QDs on InP(0 0 1) substrate by MOVPE and established a theoretical model explaining the observed epitaxial behaviour. In variance with the classical Stranski-Krastanov growth, we show that during the growth there is an intermediate stage whereby although first large 3D islands are formed, an increased density of small QDs is formed concurrent with the shrinkage of the large 3D islands. As a result, the growth can be divided into three regimes: 2D layer growth, large 3D islands growth and QDs growth. To explain this evolution, a thermodynamic model has been developed accounting for the process driven by surface energy, elastic relaxation energy and inter-island interaction energy. It will be shown that the balance between the surface energy and the elastic relaxation energy provides the transition from 2D layer to large 3D islands (around at 3 ML of InAs growth). This model also supports the energetically favourable truncated pyramidal shape for large 3D islands and the spherical cap shape for QDs. We show in this paper that a balance between surface energy, elastic relaxation energy and inter-island elastic interaction explains the volume shrinkage of the early large 3D islands towards the formation of small QDs in high density. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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