Suppression of Surface-Related Loss in a Gated Semiconductor Microcavity

We present a surface passivation method that reduces surface-related losses by almost two orders of magnitude in highly miniaturized GaAs open microcavity. The microcavity consists curved dielectric distributed Bragg reflector (DBR) with radius $\sim 10$ $\mu$m paired GaAs-based heterostructure. heterostructure semiconductor DBR followed an n-i-p diode layer quantum dots the intrinsic region. Free-carrier absorption doped n- and p-layers is minimized positioning them close to node vacuum electromagnetic-field. surface, however, resides at anti-node field results significant loss. These are much reduced passivation. strong dependence on wavelength implies main effect eliminate electric field, thereby quenching below-bandgap via Franz-Keldysh-like effect. An additional benefit scattering surface. important other nano-photonic devices which rely GaAs-vacuum interface confine electromagnetic field.