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Structure of GaN quantum dots grown under “modified Stranski–Krastanow” conditions on AlN

2003; American Institute of Physics; Volume: 94; Issue: 4 Linguagem: Inglês

10.1063/1.1592866

1520-8850

N. Gogneau, D. Jalabert, E. Monroy, T. Shibata, Mitsuhiro Tanaka, B. Daudin,

Semiconductor materials and devices

We propose a procedure to grow GaN quantum dots (QDs) on AlN by using the Ga surfactant effect in plasma-assisted molecular beam epitaxy. Self-formed GaN islands were spontaneously generated under vacuum, after evaporation of the Ga bilayer stabilizing the two-dimensional GaN layer grown under Ga-rich conditions. Island characteristics (size and density) are studied as a function of the nominal amount of GaN deposited. We demonstrate that the QD density can be controlled in the 3×1010 cm−2–2×1011 cm−2 range. It is shown that beyond a given amount of GaN nominally deposited, there is a coexistence between elastic and plastic relaxation, with GaN islands being formed on a partially relaxed two-dimensional GaN layer thicker than two monolayers.