GaN microcavity structure with SiO2∕ZrO2 dielectric distributed Bragg reflectors was fabricated by means of transferring an InGaN∕GaN multiple quantum well (QW) structure from the (111) Si substrate onto a sapphire carrier and wet-chemical etching of the substrate. A dip in the reflectivity spectrum of the microcavity structure is observed at a wavelength of 411nm indicating the cavity resonance mode. Also, the strong influence of the cavity on the QW photoluminescence has been observed. A sharp emission spectrum, with a linewidth of 3.5nm, occurs at a wavelength of 411nm coincided with the position of the cavity resonance mode.

By means of combining a very cost-effective lift-off process and a nanosphere lithography technique, we have fabricated two dimensional (2D) photonic crystal (PhC) structures on an InGaN/GaN multiple quantum well structure. Significant enhancement in photoluminescence (PL) intensity has been observed when the emission wavelength is within the photonic bandgap. Time-resolved PL measurements have shown that the spontaneous emission rate is strongly reduced by a factor of ∼4 due to the PhC effect. As a consequence, the emission intensity along 2D PhC slab-plane directions is effectively suppressed and redistributed to the direction normal to the 2D PhC slab-plane simultaneously. Temperature-dependent PL measurements have confirmed that the enhanced PL intensity is due to an increase in extraction efficiency as a result of the PhC effect.