International audienceThe authors report on the design, fabrication and operation of heterogeneous and compact "2.5 D" Photonic Crystal microlaser with a single plane of InAs quantum dots as gain medium. The high quality factor photonic structures are tailored for vertical emission. The devices consist of a top two-dimensional InP Photonic Crystal Slab, a SiO 2 bonding layer, and a bottom high index contrast Si/SiO 2 Bragg mirror deposited on a Si wafer. Despite the fact that no more than about 5% of the quantum dots distribution effectively contribute to the modal gain, room-temperature lasing operation, around 1.5µm, was achieved by photopumping. A low effective threshold, on the order of 350µW, and a spontaneous emission factor, over 0.13, could be deduced from experiments
