Figure 1
Typical SEM images and μ-PL spectra of monocrystals grown by MBE on cone-shaped patterned substrates.
(a) An InN cup-cavity, (b) a GaN nanocolumn array shown from the cleaved facet of a sample. (c) μ-PL spectra measured in: 1) the InN cup-cavity, 2) the GaN cup-cavity and 3) the GaN nanocolumns. The spectra are normalized and arbitrarily shifted for the sake of demonstrativeness; the energy counts off from the PL peak energy E0 which is taken as 0.758 eV for InN and 3.472 eV for GaN. The narrow lines are absent in the nanocolumn spectrum because their small diameter does not support the WGM modes.
