Equilibrium Compositional Distribution in Freestanding Ternary Semiconductor Quantum Dots: The Case of In(x)Ga(1-x)As
We report the findings of a systematic computational study that addresses the effects of surface segregation on the atomic distribution at equilibrium of constituent group-III atoms in freestanding ternary semiconductor InxGa1-xAs nanocrystals. Our analysis is based on density functional theory calculations in conjunction with Monte Carlo simulations of the freestanding nanocrystals using a DFT-re-parameterized valence force field description of interatomic interactions. We have determined the equilibrium concentration profiles as a function of nanocrystal size (d), composition (x), and temperature (T). The ranges of d, x, and T are explored and demonstrate surface segregation and phase separation that leads to different extents of alloying in the nanocrystal core and in the near-surface regions. We find that formation of core/shell-like quantum dots characterized by an In-deficient core and an In-rich shell with a diffuse interface is favored at equilibrium. The analysis elucidates the relationship between the constituent species distribution in the nanocrystal and the parameters that can be tuned experimentally to design synthesis routes for tailoring the properties of ternary quantum dots.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Polymer-Based Materials for Harvesting Solar Energy (PHaSE)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC0001087
- OSTI ID:
- 1065930
- Journal Information:
- J. Phys. Chem., Vol. 135; Related Information: PHaSE partners with University of Massachusetts, Amherst (lead) and Lowell; Oak Ridge National Laboratory; Pennsylvania State University; Renssalaer Polytechnic Institute; University of Pittsburgh
- Country of Publication:
- United States
- Language:
- English
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