The Stransky–Krastanow growth mode of strained layers which gives rise to a morphology transition from two-dimensional layer to three-dimensional islands is studied in details for the cubic gallium nitride on cubic aluminum nitride (GaN/AlN) system grown by molecular beam epitaxy. Besides the lattice parameter mismatch which governs this transition, we evidence the importance of two other parameters, namely the substrate temperature and the III/V flux ratio. Tuning each of these two parameters enables to control the strain relaxation mechanism of a GaN deposited onto AlN, leading to the growth of either quantum wells or quantum dots.

Self-assembled cubic GaN quantum dots have been grown by plasma-assisted molecular-beam epitaxy on cubic AlN. Atomic force microscopy and transmission electron microscopy reveal islands of a mean height of 1.6 nm and a mean diameter of 13 nm. The influence of stacking faults on island nucleation is discussed. The quantum dots show ultraviolet photo- and cathodo-luminescence with no thermal quenching up to room temperature.

Self-assembled InGaN islands were grown by molecular-beam epitaxy on GaN, following a Stranski–Krastanow growth mode. Atomic force microscopy revealed that their dimensions were small enough to expect zero-dimensional quantum effects: the islands were typically 27 nm wide and 2.9 nm high. Strong blue-violet photoluminescence of the dots is observed, persisting up to room temperature. The temperature dependence of the photoluminescence is analyzed and compared to that of InGaN quantum well and bulk samples.

Zinc blende (ZB) GaN quantum dots have been grown by plasma-assisted molecular-beam epitaxy on AlN buffer layers using 3C-SiC(001) substrates. The two- to three-dimensional growth mode transition is studied by following the evolution of the reflection high-energy electron diffraction pattern. ZB GaN island layers are further examined by atomic force microscopy and transmission electron microscopy, extracting a mean island height of 1.6 nm and a mean diameter of 13 nm at a density of 1.3×1011 cm−2. Embedded ZB GaN quantum dots show strong ultraviolet photoluminescence without any thermal quenching up to room temperature.

Zinc blende ~ZB! GaN quantum dots have been grown by plasma-assisted molecular-beam epitaxy on AlN buffer layers using 3C-SiC~001! substrates. The two- to three-dimensional growth mode transition is studied by following the evolution of the reflection high-energy electron diffraction pattern. ZB GaN island layers are further examined by atomic force microscopy and transmission electron microscopy, extracting a mean island height of 1.6 nm and a mean diameter of 13 nm at a density of 1.331011 cm22. Embedded ZB GaN quantum dots show strong ultraviolet photoluminescence without any thermal quenching up to room temperature.

We report on the optimization of growth of cubic GaN and AlN binaries together with cubic GaInN and GaAlN ternary alloys. Reflection high energy diffraction oscillations are observed for all these cubic materials which allow us to determine precisely the stoichiometric growth conditions The alloy compositions deduced from the growth rate variations by adding indium or aluminium are compared with those obtained by Rutherford backscattering spectra.