GaAs/AlGaAs quantum dots (QDs) are fabricated by low-energy ion beam sputtering and molecular beam epitaxy (MBE) re-growth. Temperature (6.5-78 K) and excitation power density (0.49-3.06 W cm −2 ) dependent photoluminescence (PL) are presented and discussed in detail. The low-temperature PL emission at 720 nm is attributed to GaAs QDs with height of ∼6.1 nm and base width of ∼23 nm, calculated based on the quantum box model with infinite potential barrier. The calculated QD dimensions are in good agreement with those obtained from atomic force microscopy (AFM) analysis. Nonradiative recombination and Auger-assisted recombination are found to be the main PL quenching mechanisms at high temperature.

Three-dimensional (3D) Ta 2 O 5 /SiO 2 photonic crystals in the visible-violet spectral region are fabricated by an auto-cloning technique on patterned substrates with triangular lattice configurations and their in-plane (the stack XY plane) optical properties are studied. Reflection measurements by normal incidence of light on to the cleaved facet of the photonic crystal reveal maximum reflections at certain photon energies. Comparison with calculated band structure demonstrates that the reflection peaks are either due to the photonic bandgap (PBG) within which the light propagation is forbidden, or due to heavy photons associated with flat bands. A two-step deposition method is adopted to insert luminescent rhodamine 590 into the photonic crystal and the emission property is strongly modified by the photonic crystal. Possible applications of such 3D photonic crystals in optical components are discussed.