The planar microcavity structure was grown using molecular-beam epitaxy. Single-mode lasing was observed at a wavelength of 960 nm for pillars with a diameter of 15 μm. At 300 K, the lasing threshold was approximately 30 mW. Increasing the pump power to 2.7 times the threshold power resulted in a mode energy shift of approximately 1 meV. This shift in the mode energy position corresponds to approximately 12 degrees of laser heating.