Effect of interfacial states on the binding energies of electrons and holes in InAs/GaAs quantum dots
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
The interface between an InAs quantum dot and its GaAs cap in {open_quotes}self-assembled{close_quotes} nanostructures is nonhomogeneously strained. We show that this strain can lead to localization of a GaAs-derived X{sub 1c}-type interfacial electron state. As hydrostatic pressure is applied, this state in the GaAs barrier turns into the conduction-band minimum of the InAs/GaAs dot system. Strain splits the degeneracy of this X{sub 1c} state and is predicted to cause electrons to localize in the GaAs barrier above the pyramidal tip. Calculation (present work) or measurement (Itskevich {ital et al.}) of the emission energy from this state to the hole state can provide the hole binding energy, {Delta}{sub dot}{sup (h)}. Combining this with the zero-pressure electron-hole recombination energy gives the electron binding energy, {Delta}{sub dot}{sup (e)}. Our calculations show {Delta}{sub dot}{sup (h)}{approximately}270thinspmeV (weakly pressure dependent) and {Delta}{sub dot}{sup (e)}{approximately}100thinspmeV at P=0. The measured values are {Delta}{sub dot}{sup (h)}{approximately}235thinspmeV (weakly pressure dependent) and {Delta}{sub dot}{sup (e)}{approximately}50thinspmeV at P=0. We examine the discrepancy between these values in the light of wave-function localization and the pressure dependence of the hole binding energy. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 657805
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 58, Issue 11; Other Information: PBD: Sep 1998
- Country of Publication:
- United States
- Language:
- English
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