Photonic Crystal Structures Based on GaN Ultrathin Membranes

Abstract

We report on maskless fabrication of ultrathin (d ~ 15 nm) nanoperforated GaN membranes exhibiting a triangular lattice arrangement of holes with a diameter of 150 nm, and show that these membranes represent an intermediate case between two-dimensional (2D) and three-dimensional (3D) photonic crystals (PhC). A calculation of the dispersion law in the approximation of scalar waves is indicative of the occurrence of surface and bulk modes, further, there is a range of frequencies where only surface modes can exist. Advantages of the occurrence of two types of modes in ultrathin nanoperforated GaN membranes from the point of view of their incorporation in photonic and optoelectronic integrated circuits are discussed.