  We present measurements of the second-order coherence function on emission
from single GaN quantum dots. In some cases a large degree of photon
antibunching is observed, demonstrating isolation of a single quantum system.
For a selected quantum dot, we study the dependence of photon antibunching on
excitation power and temperature. Using pulsed excitation, we demonstrate an
ultraviolet triggered single-photon source operating at a wavelength of 358 nm.
