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Control of Wigner localization and electron cavity effects in near-field emission spectra of In(Ga)P/GaInP quantum-dot structures

2018; American Physical Society; Volume: 97; Issue: 19 Linguagem: Inglês

10.1103/physrevb.97.195443

2469-9977

A. M. Mintairov, James Kapaldo, J. L. Merz, Sergei Rouvimov, D. V. Lebedev, N. А. Kalyuzhnyy, S. А. Mintairov, K. G. Belyaev, M. V. Rakhlin, А. А. Торопов, P. N. Brunkov, A. S. Vlasov, Yu. M. Zadiranov, S. A. Blundell, А М Можаров, Ivan S. Mukhin, Michail M. Yakimov, S. Oktyabrsky, Artem Shelaev, В. А. Быков,

Semiconductor materials and devices

Structural and emission properties of few-electron In(Ga)P/GaInP quantum dots (QDs) representing natural Wigner molecules (WM) and whispering gallery mode (WGM) electron ($e$) cavities have been investigated. QD structures were grown using self-organized metal-organic vapor phase epitaxy and deposition from $\ensuremath{\sim}3$ to 7 monolayers of InP at $700{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. Using atomic force microscopy, transmission electron microscopy, near-field scanning optical microscopy (NSOM), and $\ensuremath{\mu}$-photoluminescence ($\ensuremath{\mu}$-PL) spectra we obtained In(Ga)P/GaInP QDs having lateral size 80--180 nm, height 5--30 nm, Ga content 0.0--0.4, density $2\ensuremath{-}10\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}{\mathrm{m}}^{\ensuremath{-}2}$, and electron population up to 20 and demonstrated control of their density and size distribution. Using high-spatial-resolution low-temperature PL spectra, NSOM imaging, and calculations of charge density distributions we observed Wigner localization and $e$-cavity effects for a series of dots having quantum confinement $\ensuremath{\hbar}{\ensuremath{\omega}}_{0}=0.5\ensuremath{-}6\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$. We used these data together with time-resolved PL measurements to clarify the effect of Coulomb interaction and WM formation on emission spectra of few-electron QDs. We present direct observation of $2e$, $6e$, and $9e$ WMs; $2e$ and $4e$ WGMs; and Fabry-Perot $e$ modes and establish conditions of $e$-WGM-cavity formation in these QDs.