Photoluminescence properties of vertical emitting InP nanopillars Photonic Crystal slab on Silicon

InP-based active membrane structures transferred on Silicon exhibit promising properties for highly integrated photonic structures. Indeed, due to the high index contrast, compact two-dimensional photonic crystal (2DPC) structures can be patterned in such membranes. Slow Bloch modes (SBM) at band edges (resulting in low group velocities) can advantageously be used for directive laser emission, either in-plane for modes lying under the light line or out-of-plane. Moreover, 2DPC based on nanopillar arrays should be easily combined with refractive structures (e.g., micro-wire waveguides) unlike 2DPC consisting in hole lattices. Thus, in a more general frame, such an association is expected to lead to both new functionalities and higher integration. In this study, we investigate non degenerate SBM around the Gamma-point (k_//=0) of the band diagram of 2DPC made of pillars arranged in a square lattice. From such modes, strong lateral (SBM around a flat extreme of the dispersion characteristic) as well as vertical (high index contrast waveguiding membrane) confinements are expected; also these modes are meant to be very resonant (long lifetime as a result of the inhibited coupling with radiative modes at the Gamma-point for symmetry reasons (Ochiai, 2001)). These characteristics are highly desired in low threshold micro lasers.