Microdisk laser emission versus disk diameter.
Photoluminescence spectra taken above threshold for a wide range of microdisk diameters. Spectra are shifted for clarity. The top spectrum corresponds to a nitride microdisk directly lying on oxide following growth on a SOI substrate and underetching and the other ones to nitride microdisks standing on a Si post. The spectrometer resolution is 1 meV. Inset: Average spectra (dots) of 20 investigated microdisks standing on a Si post (all diameters), recorded above lasing threshold at P/Pthr = 1.3. The red line is a guide for the eye.